Fall and winter present special challenges for culturing. As the weather cools, the methods for keeping cultures at the proper temperature must also change.
Some cultures will actually behave differently during the winter even when the amount of light and heat are constant
How Can You Keep the Cultures Warm Enough?
There are a variety of ways to help keep cultures warm enough to culture well during cooler weather. No matter the method you choose, it is important to verify the temperature. Test the temperature by leaving a jar of water for at least an hour, then taking the temperature of the water.
Here are some suggestions:
Appliance Boost Many people have appliances in their homes such as DVRs that are always plugged in. Simply set the jar in a dish or on a plate, then place it on top of the appliance to culture.
Seedling or Reptile Mat A seedling mat from a garden supply store, or a reptile mat from a pet supply store can raise the temperature 5-20ºF above ambient temperature. This is perfect for products that need to culture at a cozy room temperature. Note: Read the instructions to verify temperature. Some mats run too warm for room temperature cultures.
Elevation It may be sufficient to simply set the culture in a high place in the kitchen, where the air is a little warmer than at counter height.
Culturing Box You may be able to maintain a “room temperature” environment by putting your culture inside a food cooler along with a jar of hot water. Check the cooler occasionally and replace the hot water if necessary, to maintain a temperature inside the cooler of at least 70°F.
Oven The oven may maintain an ideal temperature with just the inside light on. Temperatures can range from 75°-110°F, depending on the oven and bulb wattage.
Insulation Help a culture retain its own heat by wrapping it in a dishtowel.
Heat Source Sometimes just setting the culture near an incandescent lamp can provide it with enough heat to culture well. Putting it right under a lamp may be too warm.
Insulated Cooler and Water Place yogurt jars in an insulated cooler, pouring 105ºF to 115ºF water inside about ¾ the way up the jars. Close lid tightly, covering the cooler in a blanket or towel. Change out water if temperature drops below 105ºF.
Folding ProoferA convenient fold-out box that delivers predictable and accurate low-temperature heat. Digital controls provide temperature settings from 70-120ºF (21 – 49C).
Yogotherm Yogurt Incubator. This insulated container maintains temperature without electricity. Ambient temperature can have an effect on the culturing process; in cold weather, wrap with a warmed towel for added insulation.