TIPS: How to keep your sourdough starter warm
11/3/2014: A recent TFL forum post inspired me to think about ways to keep your starter warm.
Maintaining a warm temperature is extremely important to establishing a new starter. If you maintain your initial starter temperature at 82-86F, this will lead to the production of more lactobacillus than yeast, meaning a more sour/acid environment, which is important to establishing a healthy yeast and bacteria colony in your starter, especially at the beginning.
Once established, maintain your starter between 72-80F; this will help improve the speed of yeast growth. Want more lactobacillus, or more yeast activity? Take a look at this handy chart of yeast and lactobacillus growth, and choose the starter temperature that will work best for what you're trying to achieve.
I live in a part of Southern California where the weather is 75F on average about 300 days out of the year, so home warmth is generally not a problem. But what if you live where it's cold in the winter? Here are 9 ideas for how to keep your starter warm when it's cold:
1. Sunny spot by a window. Easy and cheap, with one caveat: place your starter in a shoebox or other opaque or dark-colored box. Yeast and direct sunlight don't mix well. Of course dark colors will also help keep the box nice and warm in the sun too.
2. Added 12/14/2019 - Double-insulated thermos: you could add some warm water to a double-wall vacuum-insulated thermos, then add starter in a double-bagged ziploc bag, seal the whole thing up. The larger the thermos and the more water as thermal mass, the longer it will keep your starter warm. You could probably maintain the temp heating up some metal or ceramic rods (or maybe even some sand!), placing them into a double-insulated container, and setting the starter on top. I have used this method multiple times and it works fantastically well! The trick is to not to add in too much warm water, because the bag will expand and the hydraulic pressure could cause damage to the thermos.
3. Use a water bath. Use a hotplate, slow cooker or aquarium tank heater to maintain a water bath at the right temperature, and submerge your starter container (or ziploc bag) in the warm water bath.
4. Cardboard or plastic box with a lamp. Run a low-wattage incandescent lamp/light bulb into a sealed box, turn the lamp on, and position your starter somewhat away from the lamp. A cardboard box or ubiquitous 20gallon plastic bin could be useful for this.
5. Use your oven light. Simple as that: keep your starter in your oven with only the oven light turned on. It's easy to adjust the temperature by how close you place your starter container to the light.
6. Next to your home heating system. Put it next to your home heating vent, wood stove, home furnace, water heater, fireplace, etc.
7. Old miner style/next to your body: put your starter in a small double-bagged ziploc bag, and keep it close to your body, in a shirt or jacket pocket. Just like the "old sourdoughs" used to do when prospecting. This option is the most affectionate method, and results in the most bonding with your starter ;)
8. Brod & Taylor Proofer. A lovely and functional option, if somewhat expensive. The Lexus of home proofing and warming options.
Any other ideas I missed? I'd love to hear 'em.
Comments
Heating pad with a variable temp. control.
Yes, this is a very good one. Affordable and serves multiple purposes.
With a container of hot water as the heat source. If you leave the hot water uncovered, your proofer is humidified, too.
Paul
Thanks Paul, yes this is a great idea too. How long can the cooler maintain that nice warm temp? I've never tried it.
For proofing, I often use a 4c. Pyrex with boiling water in my microwave oven with the loaves, but I find that this doesn't maintain sufficiently warm temp for more than about 1 hour.
My concern for building or maintaining a starter is that it wouldn't stay warm long enough. Am I wrong here?
How well insulated the cooler is, room temperature, dough quantity and temperature, water quantity and temperature. I don't think that phases of the moon have an effect, though...
Prior to buying a B&T proofer, I could park a 1 quart jar of 115-120F water and a 1kg or thereabouts quantity of dough in a cooler with a 30-40 quart capacity and have it maintain temperatures (not measured) that were warm enough to keep the dough happy for at least an hour, maybe longer. This with room temperatures in the 65-68F range. More or hotter water would obviously extend the duration. Repeatedly opening the cooler will shorten the duration. And so on.
Paul
I don't see why that would be true.
ultra violet light is used to purify water and kill bacteria. Works really good and direct sunlight isn't a good thing for the wee beasties,
That's UVC light which has wavelength of 254 nm. It is effectively absorbed by the ozone layer and never reaches earth surface in notable amounts. Windows filter out whatever little that does.
I was trying to find some other more definitive references on this, all I could find is this:
http://www.livestrong.com/article/252729-the-effects-of-uv-light-on-yeast/
Some UV light can be good for yeast, while large amounts can kill yeast. Is leaving your starter in direct sunlight for 6-8 hours each day going to kill your starter, or slow it down? Don't know.
I always thought this was one reason that commercial yeast packets are sealed in opaque foil, and yeast jars are dark glass/opaque.
Missing from your list of "home heating system" options is my (and my starter's) favorite 'warm spot': Snuggled up against the copper outlet pipe of our water heater tank (conveniently just off the kitchen), with an old wool stocking cap dropped over the stock starter jar or levain vessel. I've even mounted a now always-warm ceramic tile to rest on top of that pipe after it turns 90˚ and runs horizontally to the wall. Great place for proofing dough in loaf pans and bannetons, putting to good use a few of the beaucoup BTUs wasted by these dinosaurian legacies of America's halcyon cheap energy days.
Tom
Love it! Another great suggestion, thanks Tom.
Useful thread , Cranbo. Thanks!
On a Refrigerator, towards the back. This is usually warm.
Khalid
Khalid, that's a good one too. Now that I think about it, this is where I usually keep my starter at room temp. Can't believe I overlooked the most obvious answer from my own experience! :) Thanks for reminding me
Only because I own a Joule sous vide circulator.....In a 5 quart sauce pan almost full of water, I placed the small glass jar with starter on top of a 15 oz can of beans so that the starter is slightly below water level. Joule is set to 80F.
Great idea! Sous vide would be perfect for this.
I started my first starter dough yesterday I put it in the oven covered lightly this morning it was full of bubbles.
I put it in a larger container fed it and decided to put it in the oven again perhaps I don't have to wait for the 8 or 10th day to make bread.
Reading every ones post I thought if you were able to get hold Microwave and rig it so the light stays on when you close the door.
I have oven with the light on Thermometer in there saying 86.6F. Yesterday I had it in the upper smaller oven for starting and being smaller area may have gotten warmer but didn't look at the temp when I opened it to get the starter.
I am in Canada and it does get cold here in the winter so I may just use the oven or I will get another old Microwave and do the hack to keep light on.
Also I like to add I have a Dehydrator and took all shelves out turned the dial till it came on and it kept the temp at 89.9F
That's a great idea, repurposing a dehydrator for that! Especially one that has a good temperature control/thermostat built-in.
I am taking my starter mixed with buttermilk camping so we can have pancakes the next day and it is going to be chilly. The miner style sounds good in my sleeping bag but I'm concerned in a ziploc bag it won't be able to breathe?
I will have an electric griddle...maybe on really low it might work with a glass bowl with the starter on it?
Hopefully this worked out. BTW your starter doesn't need to breathe. In fact, if it's in an airtight ziploc bag it can expand like a pillow! It will be perfectly content growing in a mostly anaerobic environment for a few days.
For camping, you could always warm some water to lukewarm, and float it. Or put it adjacent to a campfire.
Another idea: if you have a double-insulated thermos or vacuum cannister, you could add some warm water to it, then throw the starter in a ziploc bag and float it in the water, and seal the whole thing up. The next morning, empty the water and pull the bag out.
Here in the UK, most homes have a hot water tank inside what we call an airing cupboard. It's where you put dry laundry to air it properly before using it. I was keeping my starter on top of the fridge, but it's modern and doesn't seem to output a lot of heat. I've just put it into the airing cupboard having given it its final (4th) feed. I'll let you know how it gets on. Before putting it in there were a few bubbles, but not too much happening!
Great suggestion Hague151!