Wednesday, 12 March 2014

Sourdough Starters

Nancy and Chad
I baked bread occasionally before I moved to the US, but I started in earnest about five years ago when I bought a copy of Peter Reinhart's Bread Baker's Apprentice and some friends gave me baking stone as a birthday present.  I made many recipes from that book over the next few years, gradually gaining a better understanding of the process and becoming more comfortable manipulating and fermenting the dough.  I bought Tartine Bread on the suggestion of a friend, and although I have some criticisms of the book as a whole, the techniques laid out in the core chapter improved my bread tremendously.  But I think I learnt the most from picking up Nancy Silverton's book.  Even though it can be frustrating in many ways (people complain that the recipes weren't sufficiently adapted for home bakers), I think any intermediate to advanced baker could pick up a lot from reading it through carefully and trying to bake her breads.
Most bread I bake these days is leavened by a sourdough starter. I have two that I bake with fairly regularly: Chad, which I keep at 100% hydration (i.e. with an equal amount of water and flour) and feed with a 50/50 blend of bread and wholewheat flour; and Nancy, which I keep at 140% hydration (i.e. with 40% more water than flour) and feed solely with bread flour. Both starters are named after the bakers whose recipes I use them in: Chad Robertson from Tartine and Nancy Silverton, formerly from La Brea
In fact, Chad has a bit of a history.  It is the son of Peter, the first starter I made using the instructions in Peter Reinhart's book.  As I remember, it involved a series of feedings and discards over about a week, with some pineapple juice added at the start, probably to lower the pH and increase available sugars. 
I baked with Peter a few times, never with any great success (the starter was fine, I just wasn't a good baker then), and eventually gave some to a friend who kept it going and transformed it into the Tartine starter, passing on discards to several other bakers along the way.  It makes me happy to think that several people in Chicago are using off-shoots of that original starter.  Meanwhile I neglected and eventually threw out Peter. A couple of months later, when I started baking again, I got some back from my friend and it was at that point that she recommended the Tartine book.  I picked up a copy of the book, christened my new starter Chad, and kept it at the same proportions my friend had it at. 
I was very happy with the Tartine loaf, and its still the bread I bake most frequently (I'll have a separate post up about it shortly).  But as my interest in baking continued to grow, I wanted to try some other kinds of dough, so I picked up a book that had been recommended to me by a professional baker some time ago: Nancy Silverton's Breads of La Brea Bakery.  Rather than converting Chad to her proportions, I decided to make a new starter with her instructions.  This involved harvesting yeast from the skins of grapes, by immersing the fruit in the mixed flour and water using a cheesecloth bag.  Silverton's process is famously wasteful, require large amounts of flour and regular feedings and discards.  I don't know that I would recommend it, but Nancy made some lovely bread when I first started using it.  It may be pure suggestion, but the starter and bread both seemed to have an almost wine-like aroma to them.
These days I use Chad more than Nancy, but I keep Chad in the fridge between bakes, where as Nancy lives out on the counter.  This is partly because I have been trying to bring Nancy back from a 6+ month neglect.  It worked to some extent---the starter is active again---but I haven't had time to get back to a regular cycle of feedings and bakes yet, so it is not at its best.  What's more, with the starter out on the counter its much more important to feed it regularly so that the bacterial population doesn't get out of control, and I often forget or simply don't have time to do this.
Chad lives in the fridge, but I pull it out to bake with at least 2 or 3 times a week.  As a result it remains very active, and I don't need to feed it more than once before baking.  At any rate, I like the bread it produces and it rises without difficulty.  I've been wondering lately if I couldn't improve it further by taking Chad out of the fridge and feeding it regularly on the counter.
I should say a little bit about the differences between the starters.  My understanding here is fairly limited, but here's what I know.  Drier starters like Chad (100% hydration---so not that dry!) tend to end up with a higher proportion of acetic acid than lactic acid; the drier condition also favour yeast over bacteria, so the resulting bread is often less tangy and sour.  This is especially true of the Tartine loaf, which uses a relatively small proportion of young starter.  Wetter starters like Nancy favour the growth of lactobacillus and other souring bacteria, and often produce a higher proportion of lactic acid.  This is actually a smoother, more pleasant tasting acid than acetic (for brewers, its the difference between a crisp sour berlinerweisse, and a vinegary one), and perhaps accounts for the wine-like aromas I associate with Nancy.  The resulting bread is often more tangy and sour, both because of the higher bacterial population of the starter and because you tend to use more of it to leaven the dough since the yeast numbers are lower (at least, I think that's why---you can find out more about these things by finding posts from Debra Wink on The Fresh Loaf).
Since conditions in wetter starters tend to favour bacteria, you have to keep up with regular feedings to keep their numbers in check, especially if baking in a hotter climate.  The initial feeding favours yeast slightly over bacteria, so by feeding regularly you give the yeast an advantage.  This is very important if you are trying to rescue a starter that has been neglected or just become too sour over time.  Regular feedings and discards will help to change the population back to something that will produce a pleasant loaf.

One more note on high hydration starters: they make excellent pancake batter!  The resulting pancakes are fluffy, light, and tangy. Nancy Silverton includes a recipe in her book for use with her starter: 2.2 lbs starter, 1 tsp baking powder, 1/2 tsp baking soda, 1/2 tsp salt, 2 eggs. 2 tbsp maple syrup; whisk together and cook.  Easy.  But I'm sure you could make also use a 100% hydration starter if you added more liquid to the batter (although the resulting pancakes might be less tangy).

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