Yogurt at home, plain and simple

There’s a satisfying simplicity in the unadulterated tang of plain yogurt.

Its pure flavor makes it a versatile player – a bright base for a bowl of breakfast granola, the start of a zesty sauce or dip, a sneaky substitute for sour cream dolloped atop a bowl of chili.

It’s simple in its ingredients, too: milk and live active cultures. With no added sugar, flavors or thickeners, yogurt is surprisingly easy – and cost effective – to make at home.

If you prefer the kind of yogurt that leans toward dessert, if you’re drawn to flavors like key lime pie and crème brûlée, you might not think homemade is the way to go. But add a spoonful of raspberry jam and a sprinkle of crunchy granola, and even a self-professed Yoplait-eating skeptic will scrape her bowl clean.

Getting the right balance

Making your own yogurt allows you to tailor it to your own taste. Thickness, fat content and level of tanginess can all be controlled in the yogurt-making process.

Milk with higher fat content produces thicker yogurt. I tend to prefer low-fat yogurt – creamier than its fat-free counterpart but not so guilt-inducing as those cream-at-the-top whole milk types. Some recipes suggest adding gelatin or milk powder to produce a thicker product. Greek-style yogurt gets its thickness from an extra step – straining off the extra liquid, called whey, after the yogurt is made.

To get thicker yogurt without extra additives or extra time, it’s possible to control consistency during the cooking process.

According to the National Center for Home Food Preservation, holding the milk at its top temperature – about 200 degrees – for 20 minutes results in a thicker finished product. Leaving the milk mixture undisturbed during the incubation time helps achieve a consistent smooth texture.

And the longer it incubates, the tangier the yogurt becomes. If you prefer a mellower end product, aim for the shortest incubation time possible, around five or six hours, which should be just long enough for the yogurt to set. If you’re a fan of the tang, let it rest at least eight hours, and even overnight.

Doing the math

All-natural plain yogurt costs anywhere between $2.75 and $4.29 a quart, depending on where you shop, the quantity you buy and whether it’s organic.

By contrast, organic milk costs as little as $1.30 per quart when you buy it by the gallon, and closer to $1.90 per quart if you buy a half-gallon. Add to that about 25 cents’ worth of yogurt for your starter, and a quart of homemade yogurt will cost you $1.55 to $2.15 per quart.

While making yogurt takes a bit of time, most of it is inactive, hands-off time, and given the cost savings, it’s time well spent in my book.

So very cultured

Simply put, yogurt is made by adding cultures to heated milk, then letting the milk rest while the cultures do their thing.

More specifically, it’s the cultures Streptococcus thermophilus and Lactobacillus bulgaricus that give yogurt its trademark consistency and tang.

Precise temperatures are crucial. The milk must first be heated to between 185 and 200 degrees, which alters the milk proteins so the yogurt will set properly. Then, the milk has to cool to between 110 and 115 before adding the cultures. If it’s too hot, it can kill the cultures; too cool and they won’t grow.

At the right temperature, somewhere between 90 and 110 degrees, the cultures create lactic acid, which acidifies and thickens the milk. The cultured milk needs to incubate at this temperature for several hours – anywhere from five to 12 – for the milk to become yogurt.

Yogurt cultures are available in a few forms. You can purchase yogurt starter kits at many health food and some grocery stores, but the most readily available source of these starter cultures is yogurt itself. Choose a yogurt that contains these live, active cultures, and one you like the taste of, for your starter.

Incubation information

Electric yogurt makers will hold your heated milk mixture at the right temperature, but there’s really no need for a specialty appliance.

I use glass canning jars and my oven.

Preheated to its lowest temperature, the oven holds just enough heat after it’s turned off to make a perfect incubation station. I pour the yogurt mixture into clean glass jars, screw the lids on tight, wrap them in a towel and place them in a cast iron Dutch oven (which I’ve warmed in the oven while it preheats). The residual warmth in the cast iron helps the yogurt hold its temperature long enough for it to set.

If you have a gas oven, the warmth of the pilot light may be enough. You could also place your jars of yogurt mixture in a pot filled with warm water and place it on the burner of a gas range with the pilot light on.

A friend of mine sets her jars in an insulated cooler, pours warm water in around them, and lets it sit on her counter until it’s done. Some people use an electric heating pad instead of the warm water.

Incubation times vary, and you can safely let your yogurt incubate overnight. I find this easiest since it means I won’t be monopolizing my oven at dinnertime.

Plain low-fat yogurt

Ingredients:

1 quart organic milk, nonfat, low-fat or whole

¼ cup low-fat plain yogurt containing live active cultures (Choose one you like the flavor of. I use Nancy’s.)

Equipment:

Candy or instant-read thermometer

Large pot

Large spoon

1 quart-size glass jar or 2 to 3 smaller jars, with screw-top lids

Small bowl

Whisk

Canning funnel, optional

Incubation set-up (any of the following):

For oven method: Cast iron Dutch oven and a thick towel

For countertop method: Insulated cooler and warm water

For heating pad method: Large pot or insulated cooler and electric heating pad

For pilot light method: Large pot and warm water

Process:

Wash all your equipment in hot, soapy water before you begin.

If using oven incubation method: Place towel inside cast iron Dutch oven. Place Dutch oven in oven and preheat to its lowest setting, around 170 degrees.

Heat milk in a large pot, stirring occasionally so it doesn’t scorch, until the milk reads 185 to 200 degrees on your thermometer.

If thicker yogurt is desired, keep the milk on the heat at 200 for 20 minutes, continuing to stir.

Remove the pot from the heat and let cool to between 110 and 115 degrees. You can speed the cooling process by placing the pot of hot milk in the refrigerator or an ice bath.

(If you’re incubating in the oven, turn the oven off at this point. You don’t want it too hot.)

While milk is cooling, place the ¼ cup starter yogurt in a small bowl. When milk has cooled to between 110 and 115 degrees, whisk about 1 cup of the milk into the yogurt, then add it back into the large pot of milk, stirring thoroughly. This helps distribute the yogurt cultures throughout.

Pour milk mixture into a clean glass jar or a few smaller jars, if you prefer. A canning funnel can help make this process less messy. Screw the lid(s) on tight.

Place jars in whatever incubation chamber you’ve decided on. Leave undisturbed until set, 5 to 8 hours, or overnight.

Store yogurt in refrigerator for up to two weeks.

Top topping

I like to eat my yogurt with granola for breakfast or a satisfying afternoon snack, and my current favorite recipe comes from “The Smitten Kitchen Cookbook” (which I’ve adapted ever so slightly).

Deb Perlman’s Big Cluster Maple Granola uses maple syrup as both sweetener and liquid, eliminating the need for the copious amounts of oil some granola recipes call for.

And her secret-weapon ingredient – a lightly beaten egg white – holds the granola together in clusters that rival what you can buy at the store. As Perelman puts it, “Nothing ‘glues’ quite like protein.”

Big Cluster Maple Granola

3 cups rolled oats

1 cup unsweetened coconut

1 cup walnuts or pecans, coarsely chopped

¼ cup toasted wheat germ

2 tablespoons olive oil

½ teaspoon salt

½ to 2/3 cup maple syrup

1 teaspoon vanilla

¼ teaspoon ground cinnamon

1 large egg white

1 ½ cups dried cherries or other dried fruit

Preheat oven to 300.

Mix together olive oil, maple syrup and vanilla. In a large bowl, combine wet ingredients with all other ingredients except the egg white and dried fruit. Toss to coat evenly.

Whisk the egg white until frothy. Stir into the granola mixture, distributing evenly.

Spread in a single layer on a parchment-lined baking sheet. Bake 45 to 55 minutes, until evenly browned and dry to the touch, rotating pan about halfway through if needed.

Cool completely on a cooling rack. Break into clusters and toss in dried cherries.

Store up to 2 weeks in an airtight container, or longer in the freezer.