http://www.cooksscience.com/articles/feature/ice-cream/
The primary ingredients in ice cream are:
Fat (usually dairy, egg yolks)
Water
Sugar or substitutes
Flavorings
Stabilizers / Emulsifiers
eg lecithin from egg yolks
http://icecreamscience.com/the-effect-of-emulsifiers-on-ice-cream-texture/
http://www.icecreamgeek.com/?p=664
Cornstarch must be cooked to 95°C (203°F) before thickening begins. Arrowroot becomes slimy when mixed with milk products
https://food52.com/blog/21507-for-the-silkiest-ice-cream-add-one-ingredient (cornstarch)
Textural challenges focus around preventing large ice crystals.
Questions:
Do we need eggs? They add a lot of complexity and time to a recipe, due to their precise heat requirements, and the subsequent cool-down.
Can we lower fat content? Fat can coat the tongue, and cloud flavors, but improves mouthfeel.
How does dry milk powder vs cream work?
https://food52.com/blog/17663-this-super-creamy-vanilla-ice-cream-required-many-taste-tests-to-perfect
nonfat milk powder is meant to increase solids, reducing ice crystals.
Dairy:
Half-and-Half: 12% fat
Light Cream: 20% fat
Light Whipping Cream: 30% fat
Whipping Cream: 35% fat
Heavy Cream and Heavy Whipping Cream: 38% fat
http://www.davidlebovitz.com/2011/09/chocolate-ice-cream-recipe/
Pineapple ice cream
Ginger ice cream
Blackcurrant (delia, p482)
http://www.kitchencurse.com/2009/11/no-churn-pomegranate-ice-cream.html
http://www.seriouseats.com/recipes/2011/01/black-sesame-and-orange-ice-cream-goma-recipe.html
http://feedproxy.google.com/~r/Tartelette/~3/i-KfW3w2F9I/dark-chocolate-brownies-ginger-ice.html
http://www.seriouseats.com/recipes/2011/06/lemon-basil-chocolate-chip-ice-cream-sandwich-recipe.html
http://www.davidlebovitz.com/2007/11/the-easiest-cho/ (chocolate ice cream)
http://userealbutter.com/2011/01/27/chocolate-banana-bombes-recipe/
Sicilian gelato: http://www.101cookbooks.com/archives/000037.html
http://fromchiletochocolate.blogspot.com/2011/02/easy-eggless-gelato.html
http://peasepudding.wordpress.com/2009/02/04/blueberry-gelato/
http://www.seanandkimberlypayne.com/thereluctantchef/2009/06/19/wasabi-ice-cream/
http://mobile.seriouseats.com/recipes/2012/05/strawberry-frozen-yogurt-recipe.html
http://www.chow.com/recipes/30374-peach-frozen-yogurt
http://blog.ideasinfood.com/ideas_in_food/2012/05/spicy-ginger-ice-cream.html
http://www.americastestkitchenfeed.com/do-it-yourself/2012/08/homemade-beer-ice-cream/
http://sweets.seriouseats.com/2013/10/do-you-really-need-to-age-ice-cream-base-overnight.html
It's a step in every egg-based ice cream recipe: "chill base overnight and churn the next day." Every pastry chef worth their gram scale will tell you how important it is to age ice cream bases—i.e chill them down in the refrigerator—before churning them.
But as we've seen before, ice cream recipes are full of procedures and biases that don't pan out when put to the test. You don't need to scald dairy or temper eggs. Fancier dairy doesn't necessarily make better ice cream. Corn syrup isn't evil.
So if you're pressed for time and want to churn your ice cream the same day you make your base, do you really need to age it overnight, or just chill it down until it's cold enough to churn?*
* From this point on we're only talking about custard ice creams made with eggs, not Philly-style or other egg-free bases, which don't usually include big claims about the importance of aging.
There's a bevy of conventional wisdom about why you should follow this step. Aging bases cools the base down, and the colder a base is before it goes into the churn, the creamier the resulting ice cream will be. Aged bases are noticeably thicker than freshly made, un-aged bases, and thicker bases tend to churn faster and creamier. Plenty of flavored liquids taste better the next day, or so it's said about every stew you've ever made.
More detailed science on the question is hard to come by, and there's plenty of pseudoscience, from "water evaporates overnight" [false] to "the milk proteins need to hydrate" [they're already in water!]. This ice cream blog—that cites scientific papers and technical books on ice cream—is the most convincing version of the scientific argument I've seen for aging your base:
First, the emulsifiers (lecithin from the egg yolks) absorb to the surface of the fat droplets....These fat globule clumps are responsible for stabilsing the air cells and creating a semi-continuous network of fat throughout the product resulting in a smooth texture and resistance to meltdown.
Second, cooling the mix to below 4°C [just under 40°F] causes the fat inside the droplets to begin to crystallise. Nearly complete crystallization is needed to promote coalescence of fat globules when the mix is frozen in an ice cream machine.
In essence, the argument goes that fat droplets in dairy need time and low temperatures to bind with emulsifiers in egg yolks and form themselves into crystals, which makes for smoother, creamier ice cream that doesn't melt as quickly. This would certainly explain why bases are thicker the next day.
But it doesn't account for any difference in ice cream's flavor, and it doesn't clarify if a home cook, with regular home equipment, would notice a difference between an aged and un-aged ice cream base once the ice cream is churned.
So in the words of Chico Powers, I decided to do some science kitchen and find out for myself.
Early last week I made a big batch of standard vanilla bean ice cream base (in this case minus the whisky) and divided it into four containers. Three of them went into the refrigerator to age. The fourth was chilled down in a simple ice bath—a small bowl nestled in a larger bowl full of cold water and ice—until it cooled down to a refrigerated-base temperature: 39°F, which for a pint of base took about 2 1/2 hours. It was then churned immediately and left to harden in the freezer.
The next day I churned another batch of ice cream from one of the aged bases. Curious to see if even longer aging produced different results, I churned the other two batches 24 hours apart for a total of four ice cream samples aged zero to three days before eating. Once all the ice creams were firmed up to the same scoopable texture, the Serious Eats tasting panel sampled the ice creams in a blind taste test, scoring them for their vanilla flavor, creamy texture, and overall preference.*
* Astute readers may notice that this isn't a totally fair test, since some of the ice creams were sitting in the freezer for longer than others. But homemade ice cream lasts about a week before any real decline in quality, and if a little freezer time was enough to override any impact of aging on flavor or texture, well, the effect isn't very strong to begin with. Without a time machine that can bring the exact same batch of ice cream base into the future, this is the best we can do.
Going in, tasters didn't know what, if any, differences there were between the ice creams. In fact, I got more than one question asking if there was any difference between the samples. After scoring their results I understood why. No pattern, no correlation between flavor and texture with overall preference, no trends of any kind. The results were all over the place, and if anything, the un-aged ice cream came out ahead.
So does aging an ice cream base make any difference once the ice cream is churned? If it does, we can't taste it. Should you want to churn your ice cream the same day you make your base, chill it down in an ice bath until it drops below 40°F, then go right ahead.
Aging your ice cream base may not necessary, but our tasting shows there's no downside to it either—we saw no trend between longer aging and decreased quality. And there are some reasons to consider it.
First and foremost, aging overnight ensures the base is very cold, and deep-chilled ice cream bases churn better than warmer ones. If you want to churn a base the same day you make it, you'll need to set up an ice bath to cool down your hot custard. Doing so is a big pain. You need lots of ice and two clean nesting bowls, there's a the risk of you slipping your base into the bowl of ice water, and it still takes appreciable time to chill a base down to refrigerator temperatures—upwards of a couple hours. Honestly, I'd rather cool my ice cream down in the fridge.
After tabulating the results of our tasting I reached out to some pastry chefs who make ice cream regularly. Though they all age their bases overnight, none were surprised by our results. They did, however, offer some other thoughts on aging bases.
For Stella Parks of Table Three Ten (you may know her as Bravetart), ice cream bases aged overnight spin up a little lighter and fluffier than when they're un-aged, giving her an extra scoop or so per [large] batch—handy when you're a pro pastry chef with a bottom line. This lends further empirical credence to the idea that aging bases allows fat droplets to firm up and network to form a more stable ice cream that holds air better.
Ryan Butler of the Highlands thinks that most flavors intensify overnight (though some, like alcohol, dissipate), enough so that he withholds final seasoning of the base until it's aged. While I'd have to taste an aged and un-aged base side by side to see if that pans out for our vanilla, I'd definitely agree that aging a base gives you a chance to revisit an ice cream base after taking a break. Your palate is refreshed, the flavor has had time to chill down, and you can make any fine-tuning adjustments you'd like.
Tracy Obolsky of North End Grill offers another compelling reason to age your base: if you're steeping flavors into an ice cream, continuing to steep them overnight intensifies the flavor all the more. "With my toasted coconut ice cream, I used to steep the coconut and then strain it out. Now I leave the coconut in overnight and it's like a punch in the face of coconut." But take note that this is about direct contact between a base and a flavoring agent, not aging a base on its own; Obolsky imagines that "in a side by side comparison, the average person probably can't taste the difference between aged and un-aged bases."
Which brings us back to where we started. Do you need to age ice cream base before you churn it? Not really, or rather no longer than it takes to cool it down. Does it hurt? No way. So go forth, ice cream makers, unimpeded by science or tradition. Do what your schedule allows, keep cool, and your ice cream will turn out creamy and delicious.
http://sweets.seriouseats.com/2012/07/whats-the-difference-between-gelato-and-ice-cream.html
What's the Difference Between Gelato and Ice Cream?
After "what's your favorite ice cream?", the question I get asked the most as an ice cream maker is "what makes gelato different from ice cream?" How does gelato get that soft, elastic texture and slow-to-melt milkiness compared to ice cream's richer, creamier body?
It comes down to three factors: fat, air, and serving temperature. The more complicated answer? Things aren't always clear cut: this is food, not phylogeny, so individual recipes can blur the lines between the two. But there are some basic differences to keep in mind.
All ice cream is mostly water, and as water freezes, it forms hard, crunchy ice crystals. Besides great flavor, the ultimate goal of ice cream making is to keep those crystals as small as possible through added ingredients and technique. Here's how ice cream makers fight crystallization:
Emulsifying fat into a base (or using already emulsified ingredients, like cream and milk) sticks fat molecules in between water molecules, literally getting in the way of ice as it freezes.
Sugar also forms a physical barrier to crystallization, just like fat. When dissolved in water, it forms a syrup with a lower freezing point than plain water, and the sweeter a syrup is (i.e. the higher the concentration of sugar), the lower the freezing point becomes. As water starts to freeze in a syrup, the unfrozen water becomes, in effect, a more concentrated syrup. This process continues until you have a bunch of small ice crystals in a sea of syrup so concentrated that it'll never really freeze.
Air is incorporated into ice cream during the churning process. Just like a light, fluffy angel food cake is easier to cut into than a dense fruit cake, a more aerated ice cream is easier to scoop, and has a fluffier, less dense texture.
The temperature ice cream is stored at also has an obvious effect: colder ice creams are harder and more solid, while warmer ones are softer, with a looser texture.
There are some other tricks to keep ice cream soft, such as alcohol, starch, protein (in egg and milk), and natural stabilizers like guar gum and carageenan, but the top four above are the big factors at play.
Compared to today's American-style ice cream (that's one made with egg yolks, as is basically the new standard in home recipes and commercial products), gelato has less fat in the base and less air churned into it during the freezing process. American ice creams are heavy on the cream, and have a fat content, by American labeling law, of at least 10% (considerably higher in most homemade and many premium versions). Gelato, by comparison, uses more milk than cream, so it doesn't have nearly as much fat. Additionally, it usually—but not always—uses fewer (to the point of none) egg yolks, another source of fat in custard-based ice creams.
American-style ice creams are churned fast and hard to whip in plenty of air (called overrun), which is aided by the high proportion of cream in the base. The most high-end ice creams have an overrun of 25% or so, which means they've increased in volume by 25%; cheaper commercial versions can run from 50% to over 90%, which gives them a light, thin, fast-melting texture that isn't very flavorful (those bites are a quarter to a half air!). Gelato is churned at a much slower speed, which introduces less air into the base—think whipping cream by hand instead of with a stand mixer. That's why it tastes more dense than ice cream—it is.
And what about sugar? Well, sugar levels vary wildly in ice cream and gelato recipes, so there's less of a hard difference there.
If you make ice cream at home, you may be wondering about your ice cream machine: does it churn at ice cream speed or gelato speed? The truth is, most of the consumer models on the market churn at about the same speed, none of which are as fast as the commercial machines used to make American-style ice cream. But you can make both ice cream and gelato in your machine—remember, air is only one of the differences between them.
All these differences give gelato a more dense and milky texture that's less creamy than ice cream. It's not thin, but it lacks the plush, buttery fullness of its American cousin. Some say that gelato has a more intense flavor than ice cream, since it has less of the tongue-coating cold fat that gets in the way of tasting things. But I think it's more accurate to say that gelato's flavors come through direct, hard, and fast, then melt away clean. A good, flavorful ice cream can have just as intense a flavor, but you'll taste it differently. One isn't necessarily more flavorful than the other.
Temperature's the Key
So if gelato has less fat than ice cream, and less air pumped into it, why is it not as hard as a brick? How does it get that super-soft, almost elastic texture that looks like a swirl of frosting more than a scoop of ice cream? It's the last big factor: temperature. Ice cream is best served at around 10°F; gelato cases are set to a warmer temperature. If you freeze gelato really cold, it'll turn right into the dense, relatively-low-fat brick it has the potential to be. But when warm, it's that perfect soft-but-not-soupy consistency. If you stored ice cream at a much warmer temperature, it'd get too soupy: the high fat in water emulsion would melt too fast.
I've been following the common naming convention in this post, calling American-style ice cream "ice cream" and Italian-style "gelato." But here's the thing: gelato's just the Italian word for ice cream. Though it does stick to the tendencies I've pointed out above, individual recipes do vary. Some call for cornstarch, others for egg yolks; some use higher amounts of sugar and others use less.
But it's all ice cream, just how soft serve is just warmer, freshly churned ice cream, and frozen yogurt is just soft serve made with yogurt as the dairy base. Sure, we can quibble over names and definitions, but at the end of the day, it's all one happy frozen, creamy family. We can argue about differences, or we can sit down and dig in to a pint together? I know which I'd rather do.
Use Invert Sugars Like Corn Syrup for Smoother, Less Icy Sorbet
Here's a little primer on how corn syrup gets made.
First, corn cobs are squeezed under extreme mechanical pressure to extract all their starchy, sugary juices. The juice is cooked with calcium hydroxide (lime) to kill any enzymes, after which it's cooked further in big pots until most of its water evaporates and it concentrates down to a thick syrup. The syrup gets so saturated that sugar crystals fall out of the solution. The crystals are then drained, centrifuged, dried, and bleached of impurities with sulphur or carbon dioxide.
Oh, wait, I got my notes mixed up. That's the process for refining sugar from sugar cane.
After years of making ice cream and sorbet, I have no bigger gripe than hearing complaints about using corn syrup in recipes. "I don't like using unnatural or processed foods," people tell me. "I just don't think corn syrup is good for me."
You're right. Corn syrup isn't good for you. But neither is refined sugar, or ice cream for that matter. If using highly processed ingredients is a problem for you, you may want to rethink making desserts from scratch. And to be clear, we're not talking about high fructose corn syrup. The Karo syrup you buy at the grocery store is an entirely different product.
When recipe writers call for corn syrup, they aren't doing it for kicks. So why do I use it in some of my sorbets and sherbets? Because corn syrup is an invert sugar, and invert sugars make sorbets smoother and less icy. The pros use invert sugars in some of their recipes, and you should too.
What's so special about invert sugar? It has two properties conducive to good sorbet:
Invert sugars are more viscous than sugar syrup. Many sorbet recipes call for making a syrup of sugar and water, then adding that syrup to a fruit purée. If you've done this, you've probably noticed that the sugar syrup you make isn't very thick. Corn syrup, on the other hand, is quite viscous, and it adds a rich, full-bodied texture to a sorbet base. The thicker a sorbet base, the creamier it'll be.
Many invert sugars are less sweet than table sugar. Nothing impacts the texture of a sorbet more than how much sugar is in it. Sorbet needs plenty of sugar to stay soft and scoopable, and sometimes the amount of sugar you need for a smooth texture makes a sorbet that tastes candy sweet. But if an invert sugar is less sweet than table sugar, you can use more of it without killing the sorbet with sweetness.
Invert sugars also resist crystallization, which isn't too vital for ice cream but is a big help for candy makers.
Four lemon sorbets with equal sweetness, but made with different amounts of corn syrup and sugar.
Now let's look at corn syrup, which is very thick and gooey, impervious to crystallization, and only 33% as sweet as table sugar (by weight).* There are other invert sugars on the market like glucose and Trimoline (invert cane sugar), but corn syrup is the only one you'll find in your supermarket. Honey, agave nectar, and molasses are also easy-to-find invert sugars, but their strong flavors limit their flexibility.
* You can see a whole table of the relative sweetness of different sugars here. Karo corn syrup doesn't list its exact chemical composition, but we conducted some tests to pinpoint its sweetness. If you want to try this at home, mix 10 grams of sugar into 50 grams of water. Then mix 30 grams of corn syrup into 30 grams of water and taste them blind. The syrups won't taste exactly the same, but they'll be similarly sweet. On Twitter, Catherine Oddenino shared some independent lab results suggesting that Karo is a 47% dextrose equivalent syrup, which puts it right on target for a 33% relative sweetness to sugar with our own taste test.
To see how corn syrup affected a sorbet's texture, I made four batches of lemon sorbet. One was my standard recipe, made with all corn syrup, which I like for its balance of sweet and tart flavors as well as its lush, ice cream-like texture. I also made three other sorbets, equal in volume and sweetness, with different amounts of sugar: one that derived two thirds of its sweetness from corn syrup and one third from sugar, one that had only one third of its sweetness from corn syrup and two thirds from sugar, and a third made with plain sugar, which had only one third of the total sugar of my corn syrup base. The Serious Eats team tasted all four blind and shared their comments.
The results were clear: even a small amount of corn syrup drastically improved a sorbet's texture. While the sugar-based sorbets won out on flavor, their texture suffered. The all-sugar sorbet sucked eggs: dry, icy, clumpy, impossible to scoop. A small amount of corn syrup added substantial creaminess, and greater amounts improved texture even more.
How much corn syrup to add is a question of personal taste. I like the super-dense, super-smooth, ice cream-like texture of my all corn syrup sorbet, though it takes a good 12 hours in the freezer to harden and it melts quickly. Others preferred the mostly corn syrup version, which wasn't quite as smooth, but close. There's no right or wrong answer here, except to dismiss corn syrup out of hand.
Ice cream is a balancing act, and each ingredient has its cost. Corn syrup is a great texture enhancer, but it's not without its flaws. To wit:
Table sugar tastes better. Karo corn syrup doesn't taste bad, but it has a slight metallic flavor compared to cleaner-tasting table sugar. Our taste test bore this difference out, and while I think a small difference in flavor is worth the immense gains in texture, a discerning palate can spot the difference side by side. If you can find them, invert sugars like glucose (which also comes powdered) and Trimoline (inverted cane sugar syrup) taste better, though both are sweeter than corn syrup.
It can dilute flavors. Since corn syrup is a liquid, it adds volume to a sorbet while diluting its flavor. With strong citrus sorbets like lemon and orange, this isn't a problem since you're diluting the juice with water anyway, and some of that water can be substituted out for the water in corn syrup. But in my root beer sherbet for example, it's important to use a boldly flavored root beer so its flavor stands up to the blandness of the corn syrup. The more subtle your sorbet's flavor is, the higher a ratio of sugar to corn syrup you might want to use, as that'll dilute your other ingredients less.
Not all sorbets need corn syrup. Thick ones like strawberry, cherry, or peach, for instance, are viscous enough that table sugar works just fine. (My general rule is that if you can make jam out of the fruit, it doesn't need corn syrup to improve its texture.)
When it comes to dessert, ice cream is forgiving stuff. It's easy to modify to your tastes, and if you don't like the end result, you can always melt it down, add some ingredients, and churn it again. I'm not saying you have to use a pint of corn syrup to get good sorbet. But it's an ingredient worth exploring for its versatility and handy chemical properties. Just remember that there's more than one kind of sugar out there, and you don't reach next-level ice cream Jedi status until you've tried them all.
http://sweets.seriouseats.com/2013/08/how-many-eggs-should-i-use-to-make-ice-cream.html
Do I Need to Use Eggs in Ice Cream (and How Many?)
Why does one recipe for ice cream melt fast and loose, while another stays cool and scoopable after resting on the counter for 15 minutes? Why are some ice creams so dense and rich that you almost have to chew them? And why do some ice creams taste full-bodied and almost warm while others are dead-ringers for frozen cream?
The answer, at least a partial one: eggs.
Eggs, specifically egg yolks, play several roles in homemade ice cream. You can make tasty ice cream without them, but there's a reason that almost every recipe published in the last 50 years calls for them. Here's why:
After water, egg yolks are mostly fat and protein. Fat, which freezes differently and less hard than water, makes ice cream soft and creamy. Protein is more valuable as it's cooked—when heated, egg proteins coagulate into a thick gel which, if you could zoom in on them at a microscopic level, would resemble a mesh of fibers. Water gets trapped in this mesh like dryer lint in a lint tray, and when it's trapped and surrounded by protein, it can't form chunky ice crystals. No chunky ice crystals = smooth, creamy ice cream.
That's not all. Egg yolks are also full of emulsifiers, mainly lecithin, which bind fat and water together in a creamy emulsion. In the same way that mayonnaise—an emulsion of oil and acid made with eggs—is thicker and more creamy than any of its constituent ingredients, ice cream made with eggs develops a richer body than ice cream made without. Eggs leverage the fat already present in the ice cream base (the butterfat in cream and milk) and make it work even further for a creamier texture.
But wait, there's more! Egg yolks also improve the stability of an ice cream, reducing its tendency to melt before you can get it from freezer to cone to mouth. This also means that egg yolks prolong the shelf life of ice cream in a freezer, since they inhibit the thaw-re-freeze cycle that ruins ice cream's creamy texture.
So eggs have a lot going on. And on top of all that, they taste good, adding a rich, custardy note that is often desirable in flavors like vanilla. Which brings us to the question at the very top of this article: how many eggs does ice cream need? Some recipes call for as little as two egg yolks per quart of finished ice cream or as many as ten. David Lebovitz, the prophet of homemade ice cream, often uses five. I call for six. Jeni's in Columbus, Ohio, uses none. Instead, her ice cream involves a special pasteurization process, some cream cheese, and a touch of invert sugar to ensure a smooth, ice-free scoop.
Is there a magic ratio of eggs to dairy that we should use? The short answer: not really. Depending on what you add to your ice cream base—fruit, alcohol, syrups like honey, or fatty ingredients like chocolate—you might need to adjust your ratio of cream to milk to eggs. But let's look at a basic ice cream base, what's often called sweet cream. It's a simple custard of cream and milk cooked with sugar and eggs, and it can be used as a master recipe for dozens of flavor variations. How much difference do egg yolks make in it?
We made six idential batches of sweet cream base, only changing out the number of egg yolks per batch. Using a standard ratio of two parts heavy cream to one part whole milk (with a little vanilla and salt thrown in for good measure), we made batches using as little as zero or one eggs per pint to as much as five. (Less eggy ice creams were topped off with additional dairy to maintain equal volume and fat level, as the dairy base has a similar fat percentage to egg yolks). The batches were then all cooked together in a 170°F immersion circulator to ensure even cooking, refrigerated overnight, and churned for 45 to 50 minutes each.
The first obvious difference is color: the eggier an ice cream, the more yellow it looks. We know that food color can have a huge impact on the perception of its flavor, so the Serious Eats team tasted the six ice creams literally blind. Eyes closed, they accepted a spoon of ice cream from intrepid intern Sam who scooped from behind a barrier. The tasters tried ice creams in a varied random order and rated them on overall preference, flavor, and texture.
The results are pretty striking (if you have trouble reading the graph, click it to enlarge). The eggier an ice cream, the more tasters liked it and the higher, for the most part, they rated its flavor and texture. The gains in flavor are present but relatively modest; the increase in creamy texture is considerable. How did the ice creams taste? The zero egg batch tasted more or less like the frozen whipped cream it essentially was. It was on the icy side, melted quickly, and felt thin on the tongue. The super-eggy ice cream was essentially frozen custard—dense, chewy, slow to melt, and very creamy. Its flavor had a decided eggnog lilt.*
* It's worth mentioning that you can of course make great ice cream with few to no eggs. Gelato is usually low on eggs, as is some soft serve, and ice creams like Jeni's show that there's more than one way to churn an ice cream. But for most homemade ice cream in the rich, buttery, American sense of the term, eggs are the way to go.
So the more egg yolks, the better the ice cream, right? Well, not entirely. While the aggregate of our tasting panel showed distinct trends, individual tasters had their own preferences. Before our tasting, Leandra announced her clear preference for ice cream so hard and icy you have to chip at it like over-frozen Italian ice, so she was all over the icier ice creams. In the days following the tasting, ad sales director Jim kept coming back for the the two-yolks-per-pint batch, which most people hated. I was most partial to the four-yolks-per-pint batch, which was plenty creamy and not as overtly eggy. Point is: what the statistical average of a tasting panel likes isn't always what you'll like. Ice cream is a very personal thing.
The bigger issue is how to generalize these results. In a sweet cream base, the only flavors going on are eggs, dairy, and maybe vanilla. Eggs boost the flavor of vanilla well, enough to make me rethink my standard vanilla bean ice cream recipe to better suit these results. And they complement others flavors too, enough so that I don't think chocolate or mint ice cream is really complete without them.
But the eggs have a way of obscuring other ingredients. The downside of rich custard is a loss, to an extent, of pure, clean flavors, and super-creamy ice creams have a way of weighing down the palate. Going for broke with ten egg yolks will ensure a smooth, rich ice cream, but it may also overwhelm more delicate flavors that you've added to your base. In some fruit ice cream, for instance, the more eggs you add, the duller the fruit taste may be. More is creamier, but not always better.
The answer to "how many eggs should I use in my ice cream" ultimately comes down to what feels right for a specific flavor, and how you want that flavor delivered to your palate. Eggier ice creams are richer, creamier, slower to melt, and more custardy and dense-feeling. The more eggs a recipe calls for, the more it'll embody those characteristics, and if you want an ice cream to be any of those things, you can add an egg yolk or two in a recipe without causing any damage. You can also lighten up an ice cream doing just the reverse.
Unlike most baking, ice cream is flexible stuff—it's easy to adjust ingredients to your taste. And once you know how eggs work when making it, you're free to fiddle as far as your cholesterol levels allow.
http://sweets.seriouseats.com/2014/03/secret-tools-and-tricks-of-the-ice-cream-pros-chefs-secrets.html
Most consumer-grade machines have a removable core that chills in a freezer and can only churn one small batch a time. Professional machines, on the other hand, range from the size of a small air conditioner (with a similar built-in compressor) to that of a free-standing fridge. One popular brand that comes in a range of models is a Carpigiani batch freezer, the Lamborghini of ice cream makers, with five-digit prices to match.
"The Carpigiani is very fast and efficient," says Julian Plyter of New York ice cream sandwich company Melt Bakery, where he churns gallons of ice cream at a time. Once his machine is up to speed, he can spin a batch in about ten minutes, a must for keeping labor costs under control. (Imagine paying someone to churn a single quart of ice cream every half hour!)
Fast freezing also means smaller ice crystals, one of the keys to creamy ice cream. And in a commercial American-style batch freezer, paddles rapidly whip air into the base, adding a discernible fluffiness to the end result. At home, my vanilla ice cream is creamy and rich; when spun in a Carpigiani batch freezer, it's spectacular: full-bodied and unbelievably smooth.
But most restaurants can't afford to drop tens of thousands of dollars on a super-fancy ice cream robot. That includes Tracy Obolsky, pastry chef of North End Grill in New York, and former SE contributors Anna Markow (pastry chef of New York's Amali) and Stella Parks (formerly ofTable Three Ten in Lexington, Kentucky), who use smaller countertop machines. The main virtue of these models, which run several hundred to over a thousand dollars, is their ability to make batches of ice cream back to back, nice for a restaurant that only needs more than a couple quarts of ice cream at a time, but less than 30 gallons.
Do these fancy machines make better ice cream? Quite possibly, but if you're thinking of investing, consider that a $750 machine doesn't make ice cream that's 15 times as good as a 50 version. You're paying for speed and output as much as quality.
If you're looking for the single greatest advantage pros have over come cooks, don't look to the ice cream machine—look to the freezer.
"The biggest key for good ice cream is keeping everything very cold," says Plyter, which is why as soon as his ice cream comes out of the machine, it goes straight into a chest freezer that maintains subzero temperatures. By contrast, most home freezers are relatively warm, and their automatic defrost cycles slowly melt and re-freeze ice cream.
Scoop shops and restaurants often have separate service freezers that warm the ice cream up to a softer, more scoopable temperature, between 0 and 10 degrees Farenheit. But once ice cream enters the service freezer, that's it—it should be kept there, eaten, or melted down, as repeated trips between storage and service freezers can make for icier ice cream.
That's not to say all the pros have it easy. At New York's Otto, gelato master Meredith Kurtzman doesn't have a super-cold blast freezer at all, so she adapts her recipes to handle relatively warm freezer temperatures. Parks had the opposite problem at Table Three Ten—they only had a subzero freezer—so she altered her recipes to be scoopable at -23°C. At New York's Empellon restaurants, pastry chef Lauren Resler times her freezer's mechanized defrosting cycle to align with the evening's dinner rush—a tricky feat of planning and training her staff.
The takeaway: The single biggest investment you can make in your ice cream is keeping it cold. Here's how; or hey, you can pick up a small chest freezer for about $250.
Repeat after me: processed stabilizers don't make bad ice cream. Bad technique makes bad ice cream.
Don't believe me? Then ask Kurtzman, who adds a proprietary blend called Sevarome as well as milk powder and maltodextrin to many of her bases. Or Plyter, who uses such a small amount of plant gums in his recipes that the first time he blind tasted a sample, he didn't realize it was stabilized at all. Resler likes the slight chewiness guar gum adds to ice cream and the creamy texture xantham gum lends sorbet. Atlanta'sHigh Road uses different stabilizer blends depending on each recipe, and even Southern Craft, an excellent—and purist—farmstead ice cream company, employs some gelatin.
"People need to stop thinking stabilizers are evil," says Kurtzman, who relies on them at Otto to manage the heat shock her ice cream endures from less-than-ideal storage conditions. But just as stabilizers don't guarantee bad ice cream, they aren't necessary for good ice cream.
Some pros just prefer to avoid them, like Obolsky at North End Grill. For Parks, "over-reliance" on syrups, stabilizers, and emulsifiers "limits creativity." At Amali, Markow eschews most refined stabilizers in favor of whipped meringue or fruit pectin in sorbets. There's no right or wrong answer when it comes to stabilizers, just the pro's personal preferences and kitchen needs.
The takeaway: Stabilizers are just one of many tools in an ice cream maker's arsenal, and every pro has their own preferences. What do they all agree on? If you use stabilizers, use them sparingly.
Most home ice cream recipes call for simple table sugar, which is chemically known as sucrose. But in pro kitchens you have more options. Liquid sugars like invert sugar, corn syrup, honey, and glucose syrup all add body, creaminess, and stability to ice cream, and a little goes a long way.
For Kurtzman's gelato, "every recipe is different." Some bases rely solely on sucrose while others supplement with glucose or trimoline. "We generally use white sugar," Plyter tells me, "but sometimes we use a 1:4 ratio of glucose to sucrose for texture."
There are more reasons than texture alone to consider alternative sweeteners. Says Parks, "Sometimes I'll supplement a base with barley malt syrup, honey, molasses, or maple syrup to add depth of flavor."
It's easier than ever to get your hands on alternative sugars, and if you're serious about your ice cream, they're worth seeking out.
It's easier than ever to get your hands on alternative sugars, and if you're serious about your ice cream, they're worth seeking out. Corn syrup is the most readily available, but others like glucose syrup and glucose powder are easy to find online. They don't just add body; they also make ice cream more resilient to melting and re-freezing, a godsend for those cursed with finnicky freezers.
A note of caution: different sugars have different levels of sweetness, so if you're supplementing your sucrose with other sugars, check out this chart (PDF) to see how they compare to table sugar.
The takeaway: Small doses of alternative sugars, when used wisely, can make for creamier, more full-bodied, and stable ice cream.
Like bakeries, ice cream shops and restaurants have the benefit of high turnover. Ice cream can turn stale like anything else, and the faster it's eaten, the better. So at Otto, for instance, a batch of gelato lasts about three days.
A pro's needs and equipment determine how long they'll keep ice cream around. At Melt Bakery, ice cream that's left undisturbed under subzero chill in a chest freezer is good for months. For a pastry chef like Resler, who deals with smaller volumes of ice cream, it makes more sense to melt down the night's leftovers and re-spin them the next day.
The takeaway: Melting and re-freezing makes good ice cream go bad, and it's somewhat unavoidable in home freezers. The best solution? Eat your ice cream quickly.
There's another technique more and more pros are adopting to make great ice cream: liquid nitrogen.
The idea is simple: if deep chill and fast freezing times make for the creamiest ice cream, why not make ice cream using the coldest, fastest freezing ingredient around?
That's what Robyn Sue Goldman does at Smitten in San Francisco. When you order a scoop of ice cream, a liquid base is poured into a mixing bowl and whipped with specially designed beaters while liquid nitrogen is poured on top. The ice cream freezes in a matter of minutes, and it's incredibly smooth with a spoonable, gelato-like consistency.
"By making every batch to order, we can throw everything out the window. The ice cream doesn't sit around and we don't need to worry about shelf life," says Goldman. That also means no need for stabilizers, alternative sugars, or in some cases even egg yolks, which emulsify and stabilize custard ice creams but also obscure bright flavors.
Making liquid nitrogen ice cream at home isn't easy, and not just because there's limited public access to the star ingredient. "The nitrogen freezes the ice cream so fast," Goldman tells me, "that you need to agitate it right so it doesn't clump up." Her machine uses two special beaters that wipe down everything—the sides of the bowl and the beaters themselves—to ensure a completely consistent texture. But hey, if you have a stand mixer and some liquid nitrogen on hand, go ahead and give a homespun version a try. You'll certainly have a fun party trick.
Liquid nitrogen ice cream shops are few and far between today, but they're growing, so don't be surprised if you see more popping up in the coming years. And who knows, maybe some day we'll see consumer-grade LN2 machines at Sur La Table right next to conventional ice cream makers.