Tuesday, 16 May 2017

The difference fermentation makes: GF sourdough from an older bread recipe

Recently when I was preparing a talk on gluten-free sourdough baking, I advised evaluating a new sourdough starter’s activity and flavor by using it in a variety of trusted yeast bread formulas. Wanting to demonstrate my own advice, I tried my starter in several yeast recipes, both other people’s and my own. With one recipe in particular, the results were so good I just had to share!  
The yeasted baguette aux céréales as it appeared on Food52.

To be clear, there are about as many ways to make bread as there are to eat it. Some other sourdough recipes I’ve developed in the past were not adapted from existing recipes and were rather different from any of the ways I make yeast-raised bread. The following is indeed a recipe for a good loaf of bread, but it’s also a demonstration of the difference sourdough makes in a loaf compared to plain baker’s yeast. My original base recipe and the multigrain baguette variation that follows were posted 6 years ago. Recent years have seen gluten-free baking tend towards fewer or single flours and less or no added starch; I too have developed plenty of recipes that reflect these changes, but as the point of this experiment was to use a familiar recipe, this formula remains as it was. 

That said - in the many times I’ve made this bread over the years, my preferred base formula has in fact evolved and changed a little from the version on the blog, including some simplifications and tweaks, but at its heart, it’s definitely still the same recipe. The major changes are as follows:
Chia instead of pectin: I’ve found that chia meal provides a similar function to the pectin I used to use, and is also superior in some ways. (There will be much more information on the starch interactions and other functions of these molecules in my upcoming book - more on this to come!) Because of chia’s mucilaginous properties, I also find it’s most effective when mixed with the water rather than added to the dry mix as the pectin was. Either one will make the dough easier to handle (among other effects), but you can also experiment with leaving it out altogether since this loaf shaped as a boule requires less handling than the original elongated loaf. 
Teff flour instead of grain: teff grains are small enough that they can be used whole in bread, as I did in the old recipe. However, the flour gives a smoother crumb. Flour absorbs water differently than intact grains, so the water’s been adjusted accordingly as well.
Sorghum option: the original recipe calls for brown rice flour, but these days I prefer sorghum. Either one should work fine in this recipe. 
Covered bake: this is a technique to trap steam in the early stages of baking, which helps the loaf expand better and form a nicer crust compared to baking normally in a home oven (it mimics the steamy conditions in a professional bakery oven). I started doing this a few years ago and now bake nearly all my bread this way - the difference is impressive. (You’ll also notice the sourdough version omits the baking powder in the original; a combination of the sourdough and the covered bake produces plenty of expansion - aka oven spring - without it.)

These above changes are still just tweaks and details - the real star of this recipe modification is the sourdough. Why? The key is the mixed fermentation by a variety of lactic acid bacteria and wild yeast, which break down molecules in the flour in a way that creates different texture, flavor, and structure than domestic yeast. This is true even of wheat breads, but the difference is especially striking in GF formulas. I believe that in the case of the properties of many GF flours, this mixed fermentation is a better fit than that of baker’s yeast.  

Gluten-Free Sourdough Boule

Part 1: Sponge
50 g sorghum flour or brown rice flour
35 g light buckwheat flour (see this post for more about the difference between standard and light buckwheat flours)
35 g garbanzo flour
25 g teff flour
120 g filtered/spring water, slightly warm 
40 g GF sourdough starter (see part 1 and part 2 of starter tutorial)
[Optional: 4 g (1 tsp) sugar (recommended if your starter has been in the fridge)]

Combine sponge flours in medium bowl. Stir together the water and starter (and sugar if using) and let sit for 15 minutes. Stir into the flours. Cover and set aside at room temp for 12 hours.
The sponge won't rise a whole lot, but it will be split on top and bubbly underneath.
Part 2: Dough - 12 hours later
125 g tapioca starch
25 g sweet rice flour
7 g psyllium husks (not powder)
3 g (½ tsp) sea salt
125-135 g filtered/spring water, slightly warm (start with 125 and add more if needed - see below)
¼ tsp chia meal
[Optional: a little sugar (2-4 g)]
[Optional: a tiny pinch (like 1/16 tsp) yeast (see Note below)] 
6 g (about 1 ½ tsp) olive oil
2-5 g honey, to taste

Combine the tapioca, sweet rice flour, salt, and psyllium in a large bowl. Stir together 125 g water and chia (and yeast and sugar, if using) and stir this into the fermented sponge, making sure there are no lumps. Pour this mixture over the dry mix and stir/knead with a spatula until it comes together, then knead a little by hand. Cover and set aside for 30 minutes. Mix in the oil and honey. Knead again by hand and assess the stiffness - add up to 10 g reserved water if necessary to make the dough smooth, silky, and slightly elastic. Shape the dough into a smooth ball. (If you have a banneton/brotform/rising basket, this is a great time to use it! You can even try using a well-floured bowl to rise the loaf. Otherwise, just let the loaf rise on parchment.) The dough will need to rise 2 hours. After about an hour or so, preheat the oven (with a baking stone or dutch oven) to 450º F to make sure it is thoroughly heated. Once the dough has risen for about 2 hours, turn it out from the rising basket/bowl (if using) and cut slashes in the top crust. Put the loaf on the heated stone (or in the dutch oven) and cover with a large metal bowl (or lid). Bake covered for the first 11 minutes, then uncover; total bake time 50 minutes.

Let the loaf cool completely (minimum ~4 hours) before cutting. (I know, I know! It smells so good you’ll want to tear it open right away! But trust me, you’ll be glad you waited - the starch structure of the bread needs to set for you to enjoy its texture.) Thanks to the sourdough, this bread should stay soft for at least a couple days if you store it cut-side down on a wooden board...but if it gets a little stiff, it will also make excellent toast!

Sourdough toast with honey: simple, yet delectable.

Note on added yeast: Dry baker’s yeast is a particular strain of Saccharomyces cerevisiae that has been selected for certain traits, including plentiful production of carbon dioxide to make bread rise rapidly. S. cerevisiae is far from the only yeast species useful for bread, though - in fact, when it comes to sourdough other yeast species are far more likely to occur as S. cerevisiae doesn’t thrive well in many starters. The wild yeasts produce better flavor and texture, but you might find the rise produced by your starter is slightly less than expected. If so, try adding the suggested pinch of yeast to your bread - you’ll still get all the benefits of the sourdough, plus just a little boost from the baker’s yeast.

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.

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!!

Tuesday, 2 May 2017

GF sourdough tutorial, part 1

A young starter, just starting out in life.
If you were following along last year when I tried making the pasta madre from an Italian GF cookbook...it was a bit of a disaster. Though it promised to be a yeast-rich traditional leaven and even got off to a promising start, I ended up with a nearly inert paste that provided neither leavening nor character and soon spoiled altogether. I still wonder if a good portion of the fault may be with differences in flours rather than the recipe itself. For one thing, milling is different - the Italian recipe, as I mentioned, calls for a grade of fine maize flour that isn’t really a thing in the US. What’s more, the rice flour I used was on the gritty side as well (a fact that wasn’t clear until I tried baking with it). For another thing, the grain varieties have different characteristics: I brought up differences between different types of rice in the pasta madre post, and a reader in Italy confirmed that Italian rice flour is likely to be from short-grain rice. (The only reason I didn’t use short-grain flour in the first place was because I was worried flour I ground myself would be too coarse - so much for that!) I honestly don’t know if the resulting difference in amylopectin ratio was enough to make any difference in this case. Perhaps someday I’ll have the patience to try again with short-grain rice flour and the proper grind/variety of fine polenta flour (if I can obtain it). 

For the time being, though, I eventually returned to a more conventional approach to making sourdough as I’ve been doing for the past few years. My posts from the pasta madre saga do contain a lot of good information about sourdough chemistry, so they’re still worth a read - see part 1, 2, and 3 - but now I’m going to teach you how to make the starter I've been using recently. Just to be clear, this is far from the only way to make a starter! But, it’s more streamlined than some of the other starters I’ve made in the past, and I’ve found this one to be quite reliable and is consistently ready in about a week. 

You may use just about any starch-rich, whole-grain (or blend with at least half whole-grain) flour(s) to make a sourdough starter. The simplest, most economical option for most people will probably be brown rice or a mixture of brown and white rice, both of which I’ve used successfully in this formula, but more suggestions are below. I am able to grind my own short-grain brown rice flour (see note above), which I’ve been getting good results with, but I know other people have also used standard brown rice for sourdough starter with no issue. The pasta madre used a blend of rice and maize/corn, and I have used this same blend for the following sourdough as well. In the past I have made sourdough with buckwheat, fine cornmeal, and also with cooked potatoes and sweet potatoes (however, these last two are not flour, which complicates things due to unpredictable moisture content and other factors - for today we’ll stick with flours). Others have had success with quinoa, millet, sorghum, amaranth, teff, and more.

Keep in mind that each flour will have its own somewhat different fermentation signature - this is due to the natural surface flora of the grain/seed as well as differences in chemical composition of the flour supporting different organisms. Also keep in mind that you must use a starch-rich flour (grains and pseudocereals) - almost anything will ferment, but starchy flours are needed to support the distinct community of bacteria and yeast that defines a sourdough. I also recommend using whole grain because the fiber and trace minerals help support a diverse sourdough community.

Stir together 50 grams of brown rice flour or other GF whole-grain starchy flour (see above) and 50 g water in a glass jar. (Please use filtered or bottled water - chlorinated tap water will kill some of the fragile sourdough organisms.)
Optional addition: a small teaspoon of raw honey can help get the fermentation going by contributing some free sugars and possibly also some enzymes. This is a tip I got from the pasta madre formula which I have found to be helpful.
Stir at 12 hours, again at 24 hours, and again at 36 hours. In other words, if you start it at 8 pm, stir it at 8 am the next morning, 8pm that night, and 8am the following morning. Don’t add or remove anything for now, just stick with the stirring. It probably won’t seem like it’s doing anything yet, but there are in fact all kinds of organisms in there that are slowly but surely beginning to ferment: stirring redistributes nutrients, introduces fresh oxygen, and helps prevent mold spores from getting a chance to grow.

At 48 hours, you will (finally!) do something different - Come back in 2 days to learn what to do next and how to get a mature starter! (Also, for a sneak peek of where we’re going with this, see here!)