Hi,
My starter appears to rise just as much in the fridge as at room temp, but more slowly, obviously.
I know the limiting factor to my oven spring has always been that I can't get my starter/levain absolutely roaring, but from a science point of view, is there any real advantage to feeding at room temp? I find it very difficult to time the peak of it and add to my dough at a convenient hour when it's on the counter.
Would a slower rise as a result of lower temps cause some of the yeast to die/stop multiplying during the process? The visual results suggest otherwise.
Thanks, Alex.
Starters can survive well In the fridge as long it doesn't get close to freezing. I wouldn't recommend it as a long-term option, as it damages the yeasts and bacteria over time...but for 1 or 2 weeks at a time it's no problem for sure. Probably even a month or so.
You can adjust the time from feeding to maturity by changing the hydration, ambient temperature or starter to feeding ratio. And even if it is past maturity (meaning it collapsed already noticeably), it's totally useable. Just might take a moment longer to ferment.
Many thanks! I just assume room temp will result in a more healthy and populous starter, and the more aggressive fermentation and dough strength needed for good oven spring. Still looking for that final big oven rise!
I have to disagree here as I just did in this thread: http://www.thefreshloaf.com/node/61946/why-doesnt-my-starter-grow-refrigerator
My starter has been in the fridge at 3.8°C/39°F for a decade. It thrives and often blows the top off the container. I only pull out what I need and then send it back to the fridge. Sometimes when there is travel that can be 2-4 weeks without being touched. I believe refrigerator type temperatures do nothing but slow the growth of both the lab and yeast, but cause no damage.
and rise times? Perhaps the dough just needs to ferment more/longer during bulking. How does the starter taste after you feed it and how does it taste when you are tempted to add it into a dough recipe?
Difficult to time a peak. Is it a rye starter? What is the room temp?
Thanks for this in-depth enquiry! Temps and rise times are typically 18C, and around 6 hours, for a 3:2:4:6 mix of starter:wholewheat:white:water, totalling 60g at 100% hydration, and I discard 48g of it before feeding again.
The reason it's so small is so that I discard very little each time (if I have to at all), and always turn the final feed into a larger levain, using 36g of the starter. I deviate on the ratios at this point. It becomes a 1:1:1:2 mix of starter:wholewheat:white:water (so higher percentage wholewheat for the levain), again 100% hydration. Don't ask me why I do this!
I don't taste starters as they're on their little cycle! I didn't know people did this. It tends to smell wheaty, and warm, as I try to catch it at the peak. I usually make pancakes out of past-peak starter - deliciously sour.
so to simplify, the feeds are 1:2:2 (s:f:w). Flour being a mix of whole wheat and sifted wheat.
A cool 18° C or 64.4° F
Very sour pancakes tells me the starter may be lopsided in the bacterial balance with a very acidic starter. Tasting the starter before and after it is fed can tell you if the acids in the starter have been diluted enough to stimulate serious growth. Here"s how I understand the little beasties. The living organisms in the starter want to survive and protect themselves until there is enough food to warrant reproductive growth. They do this by making the environment around them acidic, which slows growth and thwarts invading organisms putting them into a form of "sleep" conserving energy until they sense that something has reduced their acid surroundings.
Food, feeding them tends to reduce acidity and "wake" them up. The bacteria will respond first then grow and make more acid and gas while the yeast get on with populating until they sense a decline in available food. If not enough food is given to them, the bacteria can maintain enough acid to keep yeast barely active and with little effort keep invading bacterial intruders out of the culture. Yeasts are larger organisms and most likely more efficient at conserving energy and sense when bacteria are in contact with enough food to get them seriously activated. This in turn activates yeast activity.
Keeping a very acid starter will do little to promote a large population of yeast. Conserve yes, but not build. Again, if feedings are small and the yeast are saving their energy while the bacteria continually contribute acid to the culture, there is a steady danger each time the culture is reduced in number (discarded) and fed that the yeast population will start to decline as more feedings dilute the culture with little evidence of yeast growth. This can happen quickly with only a few feeds and therefore it is important to notice and respond to any slowing down or poor performance of the starter to give the culture time to recover.
So, how does one feed to encourage yeast growth? Feed without discarding because we don't want to throw out our yeasts before they wake up. Several ways to go about it.
One way is just to start out feeding 1:4:4 or 1:5:5 and see what happens. Warm up to 24° to 26° C let it peak in activity. Reserve some for a recipe and feed some for future use. Repeat if needed.
One of the fastest ways to reduce acid and feed a starter is to just add enough flour to the starter to make a medium dough, knead it a bit to developed the gluten and slice thickly. Soak the slices in a large bowl of warmish water for about 20 minutes (gotta check on that time.) Remove the slices and use as a preferment or allow to ferment longer. More info and videos under "washing sourdough starter". This will also be close range to 65% hydration starter.
All of this assumes the starter is tasting sour, even after a 1:2:2 feeding. It can also be that with the cooler temps, you just have to wait longer for fermentation. Cooler climates often need a larger starter inoculation into the levain. Along with warm water.
With the cool room temps, try not discarding while building the levain, try taking the peaked 60g and feeding 1:1:1 and time it. See how it compares to the discarded but larger feeding of 1:2:2. I would get the levain growing in warmer temps to encourage more yeast then reduce the temps to normal cool room temp for the long dough rises.
You have been exceptionally helpful here! Thanks so much. And I'm big on science and its varying applications, so thank you for painting a picture