Here at Chez Alaska, we use a Yukon sourdough starter that has been passed down from person to person by Alaskans since the time of the Klondike gold rush. Drop us an e-mail if you’d like to buy some; we’ve dehydrated the starter culture, and it can be reconstituted in a flash.
This past winter I did a bit of experimenting with sourdough, and breads in general. In particular, I tried to replicate the flavor and texture I associate with San Francisco-style sourdough. The flavor has a very pronounced tang, and the crust is chewy and pliable, with an almost bagel-like shine, and bubbles. I think those little bubbles are key. The interior, or crumb, is rather dense, and has a heterogenous character, holes of all different sizes.
Local supermarkets make sourdough in their bakeries, but I think for the most part, these supermarket bakeries now just thaw frozen dough rather than making their own from scratch. (I’ve visited institutional bakeries where almost everything, breads, pies, cookies comes in pre-made and frozen, and the baker’s prep work essentially consists of opening hundreds of boxes from a giant freezer.) Often this kind of sourdough is as light and airy as french bread. Seems like they just added tangy chemicals to their basic french bread/baguette dough, and called it a day. Maybe they throw in a small amount of real sourdough culture so they can label the product as sourdough.
My own initial attempts with sourdough breads turned out extremely dense, with homogenous hole structure, and hardly any discernible sour flavor. By switching from all-purpose flour to unbleached bread flour, I got a lighter, better rise and better hole structure. Unbleached bread flour has more gluten than almost any other flour, and the gluten is responsible for the rise. All whole wheat flour produces a sourdough that’s almost as dense as pumpernickel.
To increase the tangyness, I tried increasing the rise time, from 2 hours to 5, and that helped a bit. What worked even better was to make a pre-ferment with the starter and half the amount of additional flour, and then let that wet mixture work for a few hours, then let it rise in the refrigerator for a half day or more. Then I would add the rest of the flour and the salt, knead it into a good dough ball, and let that rise for a few more hours. So basically we’re talking a two day procedure, minimum. This also helps the crumb develop different-sized holes, rather than coming out like Wonder Bread.
Sourdough starter is a culture of many different wild microorganisms, mostly yeasts and bacteria. The tang comes from bacterial acids, primarily from lactobacilli, which are used for making yogurt, cheese and kimchi, and Acetobacter and other acetic acid bacteria, used for making vinegar. Enzymes already present in wheat flour break starch down into simple sugars, and the yeasts convert the sugars into CO2 gas and alcohol. Lactobacillus converts sugars into lactic acid, and Acetobacter converts alcohol into acetic acid. Refrigerating the dough inhibits lactobacilli more than the other microorganisms, leaving more sugar for the yeast, and producing more alcohol. This in turn encourages the production of more acetic than lactic acid; and acetic acid is much tangier. Letting the dough rise slowly in the refrigerator will help produce a stronger sour flavor. I suppose some people prefer sourdough that has less tang, but I figure if you’re going to go for sourdough, you might as well go all in. In either event, a very tangy sourdough bread when toasted, beats all other breads hands-down.
Longer proofing times are great, but it’s possible to overproof. When that happens, the yeast has consumed most of the available sugars, and is on a maintenance diet. Starch is still continuing to be enzymatically converted into sugar, but a a constant rate. But the dough needs to contain some free sugar for it to spring in the oven. When the dough hits the hot oven, the heat initially turbocharges the yeast into super-activity, causing the spring, or oven rise. Later, the heat kills the yeast and crusts the bread, fixing its final shape. But if the dough has overproofed, it won’t spring, and will remain very dense.
King Arthur has a solution for achieving extra tangy sourdough by adding citric acid. The recipe is here. Powdered citric acid can usually be found in the baking section of the supermarket, or sometimes in the health supplements section.
In order to get that shiny, pliable crust, you need to use a spray bottle of water, and mist the oven when you toss in the bread, to increase the humidity. Some people also place a pan on the lower shelf, and after preheating, fill it with ice or water when putting the bread in the oven.
Peter Reinhart illustrates this technique beautifully. If you’ve never heard of Peter Reinhart, he’s pretty much one of the reigning gurus of artisanal (AR´-tizz-i-nul) breads. He’s also a former monk, which is kind of cool. There are some other videos of his here, which are very informative.
He’s using a baking stone here, and has had his oven preheating for probably an hour at its hottest temperature, then he probably turns it down to 400°F or so when he slides in the bread. The baking stone will quickly transfer its heat into the dough, creating a good spring. He has let the bread rise on pieces of parchment paper to facilitate transfer to the stone, and he uses the back side of a baking sheet in lieu of a peel.
A baker's peel.
Another baking tool you might consider getting is a baker’s blade, or lame (lahm). That’s what you use to make the characteristic slashes on the top of a bread loaf. The razor blade in the lame works better and faster than a serrated-edge knife, which is the next best thing. The purpose of those slashes is not primarily decorative — the bread will crack open somewhere, and by using the lame you can control where that occurs. Especially when using a stone, the loaf can develop cracks near the bottom edge, which can cause the bottom of the loaf to become too dry.
A lame.
Edit: A friend writes that commercial bakers probably use a starch glaze to get the sourdough shine. Make a very thin glaze of 1 tsp. cornstarch and 1/4 c water, and brush on the loaves for the last 10 minutes of baking.
- Derrick Snyder