Autumn and winter present special challenges for culturing. As the weather cools, the methods for keeping cultures at the proper temperature must also change and adapt especially here in the UK when the weather can change dramatically from one day to the next.
Some cultures will actually behave differently during the winter even when the amount of light and heat are constant, they can change their shape, size and texture and you may notice that the taste also changes slightly.
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 or using a stick on thermometer.
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. If you have a free standing fridge in your kitchen this is often the perfect location as you get the warm from the appliance and the warm air that rises from the back of the fridge. This is by far the easiest and most popular method. You can vary the temperature by moving the culture from the back of the fridge (where it will be the warmest) and the front (where it will be the coldest).
- Heat tray A heat tray can raise the brewing temperature to 9C 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.Not suitable for milk kefir.
- 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 70F
- 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. Please be careful though do not accidentally cook your culture and be aware of possible contamination. This is my least favorite method.
- Insulation Help a culture retain its own heat by wrapping it in a dishtowel or similar.
- 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 so do take care.
- Airing cupboard this can work well but do be careful of contamination and potential spillages if you are also keeping laundry in there.
We do not recommend using a heat method for milk kefir as it can often be too warm for the grains and can kill them. Instead it is best just to reduce the amount of milk slightly and brew for a little longer.
Avoid keeping cultures in a laundry room as although above a tumble dryer or similar you will get a good temperature the air in the room often contains alot of contamination from the laundry. We have heard of a lot of people experiencing mould issues from this kind of location.