Smallest advisable inoculation for starter feeding?
Hi everyone. I'm new here and I want to start out by saying thanks for all the terrific information on this site. Thanks to you I am now sourdough-obsessed. lol. I wonder if all you sourdough experts could help me with a question I have.
I'm trying to figure out a feeding schedule and ratio for my 6-week-old starter that isn't too inconvenient for me or too unhealthy for the starter. I'd like to maintain a once-a-day feeding schedule at 75% hydration - once a day because that fits my schedule best, and 75% hydration because that's the level at which I feel I can best tell what shape my starter is in (I get a nice rise and fall at 75% - too thin and it doesn't rise, too thick and I'm afraid I won't be able to tell when it's overripe).
My question is, what is the smallest amount of starter I can get away with to inoculate my maintenance starter? In bwraith's blog post "Maintaining a 100% Hydration White Flour Starter," he says that he uses 5 grams of old starter to inoculate 20 grams of water and 25 grams of flour. Judging from the pictures of the bread he bakes, that seems to work just fine. But how much lower is it possible to go? 2 grams? 1 gram? 1/2 gram? At some point, if I remember correctly from biology 101 more years ago than I care to admit, the number of critters in the old starter will be so small that they might not contain whatever particular variant of yeast/bacteria that's responsible for making the starter taste like it does. As I rather like the taste of the bread I'm getting from my starter right now, I'd hate to inoculate with so small an amount that I risk having it change on me just because I used 1 gram of old starter instead of 4 or 5.
I'm no microbiologist, and I know some here are, so please correct me if I'm wrong about that. Or maybe there are so many zillions of organisms in a gram of starter that there's nothing to worry about. At any rate, has anyone tried using tiny amounts like 1 gram or even less for any length of time? If so, what were the results, both for the health and the distinctive flavor characteristics of the starter? I'm tempted to split my starter into several batches and compare the results doing 1/2, 1, and 2-gram inoculations for a week or so, but I don't know if I could sustain having to coddle 3 starters for that long.
Thanks in advance for any help.
I think for me the amount is determined by the amount of starter from my storage starter that I use to make my bread. I'm comfortable with with 10 grams of starter being refreshed with 10 grams of water and 20 grams of flour. The breads I normally make use about between 10 and 15 grams of starter for the first build. This way I have enough starter to make two different breads if I want and have enough starter remaining to refresh for my storage starter.
For my 75% starter, I use 10 g inoculate to 30 g water and 40 g flour. I'm not sure lowering the initial inoculate would add any more convenience, but I can tell you that for over 5 months now, since I've been using a 75%, the taste has remained very stable. If I let it go for 24 hrs, there seems to be plenty of food left, so I'm fairly sure you'd be good for a once a day feeding. However, if you don't bake daily, I'd recommend letting it go in the fridge. I do that often as well, and again, my starter has remained both robust and just the right flavor/sour profile for my family's taste.
- Keith
Good to know that 24 hours will work for you. Is that your regular feeding schedule, or do you usually feed more often?
Here's a little more detail on what I'm trying to accomplish. (Warning: Looooooong post follows!)
First, the convenience factor:
With respect to starter health and taste:
OK, so how have I been treating the starter so far? Currently, I'm feeding it 4 grams of old starter, 30 grams of water, and 40 grams of flour every day at 9 pm before I go to bed. This peaks at about triple the original volume by about 8 am. After it's receded a bit, at about 11 am, I stir it down. It peaks and recedes again by the early evening (interestingly, the peak volume is noticeably bigger the second time around), at which point I stir it down again and let it sit there until the 9:00 feeding.
This has worked well for a couple of weeks in that it's behaved pretty much the same throughout the two weeks, and also produces bread that I like and that seems to rise in a reasonable amount of time, But being an extreme newbie to baking in general and sourdough in particular, I don't quite know yet what I should be shooting for in terms of bread rise times and general starter behavior.
My concern at the moment is, if my starter is peaking twice between feedings, am I not feeding it enough at each feeding? I mean, my current schedule been working well for two weeks, but is it sustainable over a period of months or years? If it turns out that it's running out of food too early - but I want to stay at 40 grams of flour per once-a-day feeding - then one way to do that is to reduce the amount of old starter. This is the long-winded explanation of why I asked the original question about minimum inoculation amounts.
Sorry for writing War and Peace but I find this stuff fascinating and tend to ramble. :)
I'll leave the bulk of the questions to other folks... I'm limited on time atm : )
Try this, though! Next feeding, make 2 identical 75% starters. Treat one as usual and retire to countertop. The other, leave on counter for anywhere from 60-120 mins, then retire to the fridge. Day before you intend to use it, remove from fridge and let it finish rising at room temp, around 4-6 hours, not critical. Perform maintenance as usual (feed it). Use it around 8-12 hours later. Did it retain it's taste and ability to raise a loaf? If so, then you can repeat the process if you want to test another cycle, but I'd say you've proved to yourself that tossing it into the fridge for a few days to a week or so won't degrade it. A vast majority of us successfully refrigerate our starters between use. Once you've proven it to yourself, you can discontinue the countertop starter and sleep better. : )
- Keith
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=== he says that he uses 5 grams of old starter to inoculate 20 grams of water and 25 grams of flour. Judging from the pictures of the bread he bakes, that seems to work just fine. But how much lower is it possible to go? 2 grams? 1 gram? 1/2 gram? ===
Personally I lose about 10 grams of starter and/or (flour,water) while refreshing. To have any confidence in handling 10 grams I would have to order appropriately-sized scoops, scrapers, and crucibles from a laboratory supply company. Admittedly I am not the most dexterous person, but 1 gram of dough is virtually nothing IMHO. I would stick with (pun intended) amounts in the 25-50 gram range personally.
sPh
Welcome to TFL, hc!
I'm glad to see you have used the TFL archives. And Bill Wraith's posts are some of the most informative I have read, so I think you're going in the right direction.
I do use small amounts of starter for my refreshments: typically 3 to 5 grams, depending on how much final levain I need, and how much bread I am planning to bake. For a simple refreshment, I take 3 grams of starter and add 8 grams of water and 9 grams of flour. At 70 dF that doubles in about 12 hours, which is what I want.
Could you use just 1 gram of starter? I think so, but I haven't done it.
Temperature will be very important for what you want to do. 24 hours for doubling-time happens at low inoculation percentages and low temperatures. The best information on the subject comes from, who else, Bill Wraith.
Here's a link to a great table BW assembled on sourdough rise times:
http://www.thefreshloaf.com/node/5381/sourdough-rise-time-table
This table is dense with information, and as BW says, your starter and his may double at different rates. But using this table you can estimate what it will take to make a 75% hydration starter double in around 24 hours. Assuming your starter is like BW's, and you use whole wheat flour (he says white flour takes about 20% longer), if you fed your starter at 2.5% inoculation and kept it at 60 dF, it should take 22.9 hours to double. (Once the temp gets above 65 dF, it's difficult to keep the critters from consuming all the food in under 24 hours.)
At 2.5% inoculation you need 40X as much flour as the flour in your starter. I.e. 3.5 grams of starter has 2 grams of flour (at 75% hydration). To inoculate 3.5 grams of starter you would add 80 grams of flour and 60 grams of water. And you'd have to keep it at 60dF, which is a lot easier in the winter than the summer. If you kept it at a warmer temperature, the yeast would be done early. (That doesn't mean you couldn't use it, but your yeast might take longer to raise your dough.)
HTH!
David
Thanks for the input, everyone. That table from bwraith sure is impressive. Keith - I'll definitely keep two starters in parallel when I get around to refrigerating it, that was a good idea.
I also wonder what exactly is going on at a microbiological level at the different stages of a starter's lifecycle. When it's peaked, for example, does that mean it's reached its maximum number of organisms, and that an equal number are being born and dying throughout the duration of the peak? Or is it just that the flour's ability to rise has been maxed out, and while the number of organisms is increasing, the starter can't rise any more to reflect that?
Then, when the starter starts to collapse, what does THAT mean? More organisms dying than being born, or just progressively weakening gluten, or the same number of organisms but less active ...?
Getting in there with a microscope would be really interesting. Any volunteers? :)
Just a marginal note here for anyone passing in future: with very low inoculation refreshments - i.e. adding small amounts of starter to a relatively large amount of fresh flour and water - be aware that you are significantly reducing the acidity of the environment that the microbes in your starter are living in. This may not be optimal for the symbiotic relationship between the yeasts and the lactic acid bacteria, so it may take longer for them to grow in order to establish themselves... and more likely that something else (possibly mould, or less desirable bacteria) beats them to it.
For this reason I’d generally recommend to reduce the metabolic rate of a starter by cooling and/or reduced hydration, than low inoculations :) however, if it works for you then that’s absolutely fine!
Incidentally, I don’t know what definition people use for ‘inoculation’ but I generally take it to mean the proportion of fermented flour (i.e. weight of flour in the starter) compared to the total flour in the resulting mixture.
Can anyone help me find the link to the magic inoculation table? I've tried and tried to find. I'm so terrible at math, that I think it will really help me.
What I'm trying to do is calculate the exact amount of flour in grams for the following 700g loaf:
80% Bread flour + 20% Wheat or Rye flour
Total amount of water = ?
80% Hydration
20% Inoculation
2.5% Salt