Saturday, May 10, 2008

Chicago Green Festival

I've been really busy with grad school as the spring semester wraps up and I prepare for a big research trip, so my apologies for not doing much yet with the blog! I'll be gone until mid-June, which unfortunately means I'll be missing the Chicago Green Festival. Hope you can make it!

Saturday, May 3, 2008

Making Yogurt

I eat a lot of yogurt. Typically I eat a quart a week. I eat plain yogurt for breakfast and add jam, fresh fruit, or honey to sweeten it. I don't make much money as a grad student and I like the store-brand plain yogurt which is half the price of Stonyfield or other organic yogurts, so although I like supporting organic producers I don't usually buy organic yogurt at the store.

Yogurt containers of all sizes are typically made from plastic #5, which is more difficult to recycle. Since you can't recycle #5 in Chicago's blue bags, we've been saving the yogurt containers to reuse. We have all kinds of things stored in them in the cupboards (raisins, quinoa, sunflower seeds...) and use them for storing leftovers and home made salsa. But adding one tub a week meant we were quickly overrun with yogurt containers. I wanted to find a way to stop our plastic container buildup, and it occurred to me to make my own yogurt.

I tried making yogurt once a few years ago but it didn't work at all. In New Zealand it was relatively common to make your own yogurt using supplies from this Kiwi company, and although we never tried it, it planted an idea in my head. I decided to use powdered milk to make yogurt because we don't keep a lot of milk in the house, but I always have powdered milk on hand for when a recipe calls for milk.

In the past I'd always bought the typical store-brand instant powdered milk, but I wanted to try a non-instant milk because the flavor is better. There were basically no other powdered milk options at the local stores (even Whole Foods), and surprisingly few powdered milk options online. After much searching and researching, I decided to buy Bob's Red Mill Powdered Dry Milk from Amazon.

Here's how I make my yogurt.

Materials needed:
-2/3 cup Bob's Red Mill Powdered Milk (the amount you use will vary- read the reconstitution directions for your milk. Use the amount for making one quart plus 1/8-1/4 cup extra).
-3 1/2 cups water
-2-3 tablespoons of plain yogurt from the store (this is your starter culture)
-blender for mixing dry milk
-double boiler (preferable to a regular pot because it keeps the milk from scalding)
-candy thermometer (about $5 at the grocery)
-clean spoon
-clean quart-size container with clean lid
-a warm place to let the yogurt set for 8-24 hours
-hot water bottle for keeping warm place warm (optional)

1. Reconstitute your dry milk in the blender to make 1 quart of milk. The blender is the best way to get the lumps out, especially for non-instant powdered milk.
2. Put water in the bottom of the double boiler and put the milk in the top.
Double boiler

The basic setup

3. Heat on medium and clip the candy thermometer to the edge of the double boiler to take the temperature of the milk.
4. Stir occasionally and watch the thermometer. When it gets to 180° F, remove the double boiler from heat and allow to cool.

5. Stir every few minutes to prevent skin from forming on top of the cooling milk. When the temperature falls to 115° F, stir in the store-bought yogurt.

6. Transfer the milk/yogurt mixture to the clean quart container and put the lid on.

I reuse the yogurt containers from the store. We have so many of them!

7. Set your container in a warm place.
My warm place is a down sleeping bag in a closet with a bottle of hot water.

8. Check on it every 8 hours until it is in the consistency you prefer (longer usually results in thicker yogurt in my experience).

Notes and tips
-My warm place is a down sleeping bag in a closet. I also pour boiling water into a Nalgene bottle as an improvised hot water bottle.
-Bob's Red Mill Powdered Milk gets very frothy when you mix it in the blender. All of the foam on top of the milk keeps it warm and it can take a very long time to cool from 180° F to 115° F. If you're getting impatient, try scooping off the foam.
-To eliminate the foam problem above, mix up your milk a day or more before you plan to use it and keep it in the fridge. This gives the bubbles time to go away.
-If you don't have a double boiler (I don't think many people do), you can just use a normal sauce pan but you'll have to be careful with the heat so it doesn't scald you milk on the bottom of the pan.
-It's best to use store-bought yogurt as a starter rather than using your own home-made yogurt because 'second-generation' yogurt is a bit less predictable in flavor and texture.
-You can freeze store-bought yogurt in icecube trays or popsicle makers and thaw some when you make yogurt.
I use these popsicle makers to freeze store bought yogurt for my starter.

Do you make your own yogurt? What tips do you have?