One of my favorite pastimes in life is questioning why we do things the way we do. If the reason doesn’t make sense to me, I look for a faster, cheaper, better, or more efficient way to do it.
The following question from a reader caused me to wonder if tradition or perhaps a cook’s insecurity (if some is needed, add more for good measure) might be the reason there is so much discrepancy across the web regarding the amount of starter needed to make yogurt.
“I have a question about the quantity of “starter” in my homemade Greek yogurt. I use 8-9 cups of milk and was told to bring it all to the proper temperature on the stove, then cool down to the proper temperature then…..and, this is my confusion – you suggest 2-3 teaspoons of yogurt (starter) - when my initial recipe says to add 8 ounces – 1 cup of unflavored Greek yogurt – as my “starter”. Which is the proper amount of starter to add? Is it the 2-3 teaspoons or 8 ounces? Have I been adding far too much?”
I was inspired to experiment.
In the first trial, I added different amounts of starter ranging from 1/4 teaspoon to 1/2 cup for a pint and a half of milk (3 cups). As you can see from the picture above, they all made yogurt–even the 1/4 teaspoon. Notice all the whey sitting on top of the yogurt in the green plate row where I added larger amounts compared to the bottom row.
When I dumped the contents of each sample onto a flat plate, the contrast was dramatic! Look how much smoother and creamier the yogurt looks on the right where only a small amount of starter was added to the milk.
I combined the top row of yogurt samples containing a lot of starter and the bottom row containing much less to make Greek yogurt, my favorite. After straining and whipping, you can see the result below. WOW! Which one looks more appetizing to you? Surprisingly, the yogurt on the left is still quite edible and tasted just fine even if the texture was not so smooth and creamy.
Then it occurred to me that time of incubation could also make a difference, so I tried again. This time I used 1 quart of non-fat milk for each sample and my own yogurt as a starter with amounts ranging from 1/4 teaspoon to 1/4 cup. I didn’t even try the reader’s suggestion of 1 cup to 8-9 cups as I could already see that was overkill after my first experiment.
At four hours, they all made yogurt except for the 1/4 teaspoon. It is obviously a little too thin, especially if you want to strain it for Greek yogurt. It’s not obvious in the picture but the 4 tablespoon sample is already not as creamy. I put them all back in the oven to incubate longer.
At 6 hours, there is not much change except for the 1/4 teaspoon sample which is now nearly as thick as the others.
After 8 hours of incubation, the 1/4 teaspoon sample is just as thick as the 1 teaspoon sample and the creamiest. I tasted them all for tanginess and really couldn’t tell much difference.
Many yogurt instructions will tell you the longer you incubate, the thicker your yogurt. I’m not so sure. Except for the 1/4-teaspoon sample, they were all thick at 4 hours and didn’t get any thicker, even when incubated an additional 4 hours. There are other more important factors when it comes to thickness, which I hope to address in a future post.
Conclusion? For 1 quart of milk, 1/2 to 1 teaspoon of healthy starter is plenty. If you are going to be incubating for a long time because you are doing it overnight or for a special diet, choose the smaller amount. If incubating for a shorter time, use a little more starter, but not over a tablespoon per half-gallon of milk.
In case you’re wondering, I always use fresh non-fat milk from Braums. It makes the best yogurt EVER because they concentrate the solids of 1-1/2 gallon non-fat milk into 1 gallon (or something like that — a process I don’t quite understand). I used a previous batch of my own homemade yogurt as the starter (1 week old) which was flavored with vanilla bean paste but contained no other additives.
PLEASE NOTE: Using a different kind of milk, starter, or additives such as powdered milk or gelatin will most likely yield different results in regard to texture, thickness, and taste. Making yogurt is simple, but the results from using various techniques and ingredients can be complicated to predict. Have fun experimenting!