Making Yogurt with Mesophilic Cultures
One of the most important things to consider when making yogurt is the temperature at which it cultures.
Swings in temperature will delay culturing if too cold, or damage the bacteria if too high. Inconsistent temperatures can lead to an uneven texture or yogurt that does not set at all.
While it can be difficult to maintain the proper temperature for countertop cultures (70º-77ºF) throughout different seasons, there are several ways to better control your culturing environment to keep your starter cultures happy and thriving.
Be sure to test the temperature of the culturing area prior to making yogurt. To do this, place a jar of room temperature water in the culturing area. Then, take temperature readings at different intervals during the culturing time-frame to ensure the temperature range is correct.
Keeping Cultures Warm in Winter
1. Warm Oven
When room temperature dips below 70º F try setting your yogurt jars in a closed oven to culture. (You can place them on a baking tray to help stabilize them on the oven rack). Turn on the light or pilot light to maintain a constant culturing temperature. You may also want to leave a note on the oven to remind others of the yogurt culturing inside.
An insulated container such as the YogoTherm works to maintain temperature without electricity. This may be just the added insulation your yogurt starters need to culture properly during chillier months.
3. Hot Water Bath
Set the covered yogurt jar in a large bowl, filling the bowl with hot water. The water level should be no more than one to two inches from the top of the jar. As the water cools, remove the jar gently, pour the water out, replace jar, and add hot water.
4. Appliance Boost
Wrap the jar of yogurt in a towel, placing near or on an appliance like a wood stove or atop the refrigerator.
5. Folding Proofer
The Folding Proofer has a temperature range from 70º F to 195º F. While you don't want to raise the temperature all the way to 195º F (your yogurt cultures will be cooked!) you can set it to the temperature on the yogurt starter instructions to create a cozy and consistent temperature for yogurt to culture.
When arranging jars inside the proofer, keep jars along the edge if you don't plan to fill the proofer completely. If you will be filling the proofer all the way with jars, remember to rotate their position 2-3 times during the culturing process to help produce more even results.
6. Insulated Cooler
You can warm up your yogurt inside a cooler by putting a jar (or two) of hot water inside the cooler with your jars of yogurt. Check the temperature of the water jar(s) and replace as needed to maintain temperature.
Culture yogurt in a beverage thermos. Wrap in a towel for added insulation, if necessary.
8. Seedling or Reptile Mat
Try placing your yogurt on top of a seedling or reptile mat. This can raise the temperature 5-20º F above ambient temperature.
Set yogurt in a high place, where air is warmer than counter height.
Keeping Cultures Cool in Summer
10. Insulated Cooler
Pack your jars into a cooler, add ice packs, and keep the cooler closed tight to keep your yogurt cool on hot summer days.
11. Cool Surface
Try placing a jar of yogurt on a cool surface to help it stay cooler than its surroundings. A marble or stone board works great, but you have lots of options.
Any table or surface designed for candy-making will work. Alternatively, a metal cookie sheet with a wet towel under it, positioned on top of a cooling rack may work as well. The evaporation of the water will cool the metal sheet.
12. Cooling by Evaporation
Place jar of yogurt in a shallow container of cool water. A cooling effect occurs as evaporation takes place. Replace water if it evaporates completely.