Thursday, 4 May 2017

GF sourdough tutorial, part 2: Feeding and maintenance

If you started your starter on Tuesday, it is now two days old. (If you haven’t started yet, see part 1 for instructions.) You’ve hopefully been stirring it every 12 hours for the reasons I mentioned, but you have not refreshed or fed it yet. To get a healthy fermentation, you will now need to refresh it once a day for the next several days. 

Feeding your starter:
Here’s how to do it: remove half the mixture so you are left with 50 g starter. Add 50 g fresh flour and 50 g filtered/bottled water (a 1:1:1 ratio of starter:flour:water). Keep refreshing in this manner once every 24 hours, and also keep stirring it every 12 hours as before, and it should be ready in about one week from when you started. With this formula using brown rice flour, I find it starts smelling really nice around day 6, when I usually test it for baking, and continues to mature for another day or two. You may notice different things or on a different timeline depending on what flour you’re using; because of this, I’ve avoided going into too much detail about what your starter “should” be doing day by day. The following information should apply to all flours. (See below for signs it’s ready and how to tell if you need to alter your procedure at all.)

This 1:1:1 feeding ratio is a pretty standard one for starters of all types at 100% hydration, though some people like to further reduce the ratio of existing starter (perhaps 1:2:2). This ratio is what’s important, in order to maintain enough fresh nutrients for a healthy, robust fermentation - as nutrients deplete and waste products build up, the cells’ metabolism changes and can quickly turn into something that won’t make good bread as other species take over. We remove part of the mixture rather than just feeding exponentially in order to keep the starter at a manageable size. 

Waiting to refresh/feed until the 48-hour point is my personal twist - it seems to get the starter going faster and seems to help avoid some of the funkier stages of fermentation, probably (though I currently have no good way to verify this) due to allowing the lactic acid bacteria (LAB) to outcompete other bacterial species more rapidly by acidifying the undiluted mixture over those first 48 hours.

Discards: 
People have varying opinions on what to do with the removed portion (often termed “discard”). As the term might suggest, many people do recommend simply discarding it. This is because in a new immature starter, the mixture has not sufficiently acidified and balanced out to ensure that it contains only the desirable bacteria and yeasts - at first, there can be all kinds of things growing in there, not all of them pleasant. Nevertheless, some people do use the immature discards. (There are also plenty of examples of traditional spontaneous grain ferments that go for several days, though these are usually fermented at warmer temperatures which encourage desirable LAB.) It’s kind of up to you. A good piece of common sense: if it smells bad, definitely don’t use those discards. Smelling neutral or pleasant is not a guarantee of safety, but smelling bad is a pretty sure indicator that you don’t want to eat it! Even if it might not strictly make you sick, it’d probably taste pretty gross. Don’t feel too bad about being “wasteful” if you feel more comfortable discarding them - the flour has served a purpose. It’s natural that starters may go through a phase of smelling unpleasant in the first week - keep refreshing and stirring as scheduled and it should balance out.

Things to watch for:
Most GF starters will not look quite like wheat starters because they lack the sticky, elastic properties of air-trapping gluten proteins. While they will generally not have the dramatic height increase of wheat flour, there are more subtle cues to look for to gauge activity.
Hungry starter...
The starter above has cavernous bubbles that have grown large and collapsed; a couple of hours prior, this not-quite-mature starter was nicely domed on top but has since fallen. This is a sign the starter burnt through the available nutrients a couple hours sooner than expected. If you notice this, feed it ASAP even though it’s not the scheduled feeding time, perhaps even at a somewhat higher ratio than usual. When the starter gets really stressed/hungry, it may even smell unpleasantly sharp, like acetone. If this happens, immediately feed at a higher ratio than usual and stir frequently until it starts seeming healthier again. This is kind of a “danger zone” for the health of a starter - stressed cells’ metabolism changes, and these chemical changes in a stressed starter can result in an altered ecosystem where it can become difficult to return it to the desired balance.
Healthier starter.
The starter in the second picture has plentiful small, round, evenly distributed bubbles and bounces back to this same activity level within a few hours after a feeding. At this point it may also develop pleasantly tart and/or yeasty smells. Try to maintain it at this level of activity; if it looks like this around day 6-7, try using it to bake with. If you are satisfied with the results, you may refrigerate it (see next paragraph for maintenance instructions). If not, keep feeding it as above and test it again in a day or two.

Maintaining your starter:
Once it’s ready, it will still need some maintenance. The mature starter will still need regular feeding to stay healthy (like most other living things!) so you can either use it every day for bread, pancakes, porridge - and whatever else you can think of - and keep feeding it at the same ratio as above, or put it in the fridge to slow down its metabolism and feed it about once a week. The latter option is more realistic for most people! I tend to keep just enough starter to make 2-3 loaves before needing to replenish it, so I use it gradually until there is only a little starter left. Then when there’s only 30-40 grams of starter left in the jar, I feed it 40 g of flour and 40 g of water like usual, leaving it out on the counter for a few hours to make sure it is fermenting properly before returning it to the refrigerator.  

Troubleshooting your starter:
“My starter looks ready to use, but it’s only 3 days old!” You may see a lot of bubbles, but this doesn’t mean it’s mature - in fact, it probably isn’t even yeast producing this gas. A common culprit is any of several species of the lactic acid bacteria Leuconostoc, such as L. mesenteroides. It is a contributor to the chemical changes that pave the way for a stable sourdough. Yeasts will appear in significant numbers after the mixture has been fermented by LAB for at least a few days.
Mold on sides of jar: Carefully transfer starter to a clean jar, avoiding the mold. This is exacerbated by condensation in the jar; try moving the starter to a cooler place and/or covering the jar with a cloth or other breathable cover.
Mold on top of starter: Have you been stirring it every 12 hours? Mold does not establish easily on frequently-disturbed surfaces. It’s up to you whether you want to just remove the surface mold or start over. (Removing the surface mold is generally considered OK because whatever traces might still be in the mix are going to be both diluted by subsequent refreshments and inhibited by the fermentation process. However, if you’re allergic to mold, you may be safer just starting over.) Make sure you’re feeding & stirring on schedule, make sure your jar and utensils are clean, and avoid condensation (see above).
Starter just won’t start: With rice flour, I find it quite common for the starter to look fairly inert until day 5 or 6, when it seemingly suddenly springs to life with bubbles and begins to smell yeasty. If you’re past this point and still not noticing activity, try seeing if maybe your mixture needs a fresher source of flour (even grinding it yourself if possible), purer water (in case traces of chlorine or other chemicals might be inhibiting growth), and/or try boosting things by adding some honey or sugar. (If you’ve tried these things and are still having trouble, contact me and hopefully we can figure it out.) 


Coming up this weekend: How to use your starter to make bread, with a recipe!
Check back in a few days if you want some of this!!

4 comments:

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