http://food52.com/blog/16213-the-dairy-products-you-should-make-at-home-from-simple-to-even-simpler
Butter
You can have the best butter you’ve ever encountered in 15 minutes or less. I pop cream into my stand mixer while I am preparing lunch and let it whirl on its own. Ten minutes later, the butterfat has separated from the milk and you have butter! All you need to do is pour it through a strainer press the buttermilk out through a thin piece of muslin, shape it anyway you wish, flavor it if you please, and put it on the table or wrap it up and bring it to a dinner party as a beautiful hostess gift. (You can also use a hand-mixer or an old-fashioned butter churn which is a bit more time-consuming.)
Begin by pouring your cream into a blender or food processor. Here I’m using slightly soured raw cream. It’s too far gone to be happy in coffee, but it’s not quite solid enough to be served up as sour cream.
Blend your cream; After five or more minutes, the homemade butter will start to separate into butter and buttermilk. When you notice that happening, stop the blender and let the cream sit for a minute or two as the butter rises to the top.
Pour the buttermilk into another container, using a spoon to press as much buttermilk out of the butter as possible.
Wash the butter - pour ice cold water into the blender and blend for another thirty seconds; pour off the water.
Use a spoon or a spatula to squeeze out the last dregs of the buttermilk. What’s left is yummy homemade butter. I mix in sea salt with a spoon.
Churn, Baby, Churn
The first thing you’ll need is room-temperature cream. It will process faster and it’ll be easier to work with. Once it’s ready, place the cream in the bowl of a food processor, being sure to leave enough room for it to agitate without splashing out the top or sides. Keeping it below the halfway line is a good rule of thumb. I have a 12-cup food processor at home, and find that a quart of cream is just the right amount. Make sure that the top is securely locked in place, then let ‘er rip. The cream will whirr around the bowl, thickening and transitioning to whipped cream (feel free to stop the machine at this point and sneak a taste), then “breaking” before finally separating into milk solids and buttermilk. The butter will look like delightful little yellow clouds swimming in a cloudy sea. The whole process takes five minutes or less with a small batch. Set a fine mesh sieve over a mixing bowl or glass measuring cup and pour the milk solids and buttermilk into the sieve. The bowl or measuring cup will catch the buttermilk. Save it and use it for pancakes.
Rinse It Out
To finish the butter, rinse it under cool water, gently moving it around the sieve with a mixing spoon. You’re rinsing off the residual buttermilk, and this is important because the more thoroughly you rinse, the longer your butter will last. Continue rinsing until the water runs clear, then let the butter drain in the sieve. You can also use a spoon or clean hands to work out any excess liquid, which, if left in, could also turn the butter rancid quicker. Commercially-produced butter is washed with either a chlorinated rinse or lactic acid to help preserve it. That means your homemade batch will never keep as long as the store-bought version, but making sure it’s squeaky-clean helps.
Take It With a Grain (or More) of Salt
If you choose not to salt your butter, know that it will turn faster. (It’s essentially just more concentrated heavy cream, points out Jakubowski. Salt helps preserve it.) If you are salting, add a little bit at a time and taste as you go. You can always add more, but it’s impossible to fix a too-salty butter. A fine-grain salt will incorporate into the butter better, but a flaky sea salt will impart intense bursts of salinity. I’m a fan of both; it just depends on my mood.
There are two main varieties of butter: sweet cream and cultured. Sweet cream butter is simply butter made from fresh cream. Cultured butter is made from cream that has been allowed to ripen first. This can be accomplished simply by ignoring raw cream in your fridge for a while until it starts to sour, or you can speed up the process by inoculating the cream with a bit of yummy bacteria and allowing it to ferment at room temperature. Both options yield delicious results, but many butter connoisseurs prefer the slightly tangy depth of flavor that cultured butter brings to the table.
High quality ingredients are important; if you don’t have access to raw milk, you can learn how to make butter from pasteurized cream instead. Just try to select regular pasteurized cream if you can–avoid ultra-pasteurized (UHT) cream, since it has been heated severely, ruining much of the flavor. If it’s your only option, it’s doable, but not optimal. Regular pasteurized cream, or vat-pasteurized cream, will suit you better if you can find it.
My weapon of choice is a food processor, other options are a stand mixer, or even a blender. The stand mixer tends to fling cream all over my kitchen, so you may want to cover it with a towel or a piece of plastic wrap.
1 quart heavy cream
Sea salt
Pull the cream out of the fridge a couple hours before you plan on making butter. Room temperature cream seems to turn into butter much faster for me than cold cream.
Place the cream into the processor or blender and turn it on; The cream will go through several different stages before finally turning into butter.
First it thickens, then it turns into whipped cream, then into chunky whipped cream. Finally, it will “break.” This is when the yellow butterfat separates from the buttermilk.
Strain the buttermilk from the butterfat, and save it back for making delicious pancakes, waffles, or buttermilk biscuits.
You now need to wash the butter to remove as much of the buttermilk as possible–this will help it to not spoil as quickly.
Place the butter into a bowl, and add in several cups of cold water. (I just usually run it under my tap.)
Use a wooden spoon to gently press the butter particles together and encourage them to stick together.
As the butter gets colder, it will firm up. Dump off the cloudy water, and add fresh.
Continue to knead and press the butter to remove more and more buttermilk.
Repeat this process as many times as you need to in order to remove as much of the buttermilk as possible. (It usually takes me 3 or 4 times)
Mix in salt, to taste, if desired.
Cultured Butter
Ingredients
1 quart room temperature cream
1/8 teaspoon mesophilic starter culture (if you are making cultured butter)
Sea salt (optional)
Instructions
Mix the starter culture into the cream, allow it to culture at room temperature for 24-48 hours. (If you want sweet cream butter, skip this step.)
Place the cream in a food processor or blender, and allow it to churn until it "breaks". (Fat particles separate from the liquid buttermilk)
Strain off the buttermilk.
Wash the butter in ice cold water, pressing it together with a wooden spoon to remove buttermilk.
Rinse, and repeat until the water is no longer cloudy with buttermilk.
Add salt to taste if desired.
Wrap tightly in plastic wrap.
Store in the fridge for several days, or in the freezer for long term storage.
Buttermilk
If it comes from the byproduct of the butter-making, it couldn’t be easier. Simply pour it out of the basin in which you’ve churned your butter and you have a super fresh and light milk that is perfection for baking bread or biscuits. Cultured buttermilk is a matter of tempering regular milk with an acid (like lemon juice or vinegar) and allowing it to slightly curdle.
Sour Cream
This is just like the name implies: soured cream. Simply mix heavy cream with buttermilk and allow to sit overnight, and poof, the best damn sour cream you’ve ever had on a baked potato.
Farmer Cheese, a.k.a. Cheat’s Ricotta
Just takes a couple of steps, a saucepan, and stove. Heat full-fat milk to just about boiling, take off the heat, and add your acid of choice. Curds will form. Allow to cool, then strain through cheesecloth and devour. If you use heavy cream in this process, you will be rewarded with a mascarpone-style cheese. I highly recommend it.
Irish Farmhouse Ricotta
Makes 1 generous cup (225 grams)
3 cups (750 milliliters) whole milk
1 cup (250 milliliters) heavy cream
1/2 teaspoon coarse sea salt
3 tablespoons lemon juice, freshly squeezed
Crème Fraiche
Combine heavy cream and buttermilk in a saucepan, then heat to lukewarm. Stand at room temperature for a day, then refrigerate; it’s ready to use the next day.
Sweetened Condensed Milk
Both are easy-peasy but require keeping a constant cautious eye on their progress, which could mean an afternoon in the kitchen. Having said that, if you are making a tres leches cake and you use homemade milks, you’ll never prepare it using the canned version again.
Makes just under 1 cup
1 1/2 cups whole milk
1/2 cup granulated sugar
1/4 teaspoon vanilla extract, if desired
In a small, heavy-bottomed sauce pan, mix together the milk and sugar. Take note of where the milk reaches on the side of the pan. Over medium heat, warm the milk-sugar mixture until just steaming. Then lower the heat and simmer for about 2 hours, or until it thickens slightly. When the mixture has reduced by about half, stir in the vanilla extract. Cool completely. As it cools, the milk with thicken. Pour the condensed milk into a clean, dry airtight container (I like to use a glass jar) and store in the fridge for up to 2 weeks. Notes: This won't be nearly as thick as canned sweetened condensed milk, but it does have the same sweet, milky flavor. The vanilla is optional: It adds an extra hint of creaminess, but isn't absolutely necessary.
Yogurt
This involves heating a yogurt starter (with probiotics) with milk and then allowing it to sit covered at a constant temperature for 24 hours. Once you have your first batch, you can keep using your starter for future batches.
Makes about 13 ounces (375 grams)
2 cups (500 milliliters) whole milk
2 cups (500 milliliters) heavy whipping cream
2 tablespoons buttermilk
1/4 teaspoon fine sea salt
This requires full-fat whole milk, heavy cream, buttermilk, and rennet. Heat the milk and cream, then add buttermilk followed by rennet. Cover and leave it to set overnight, then sprinkle with a bit of salt, strain the cheese through cheesecloth, refrigerate, and serve with bagels and lox from Russ & Daughters the next morning!