Wednesday, July 4, 2018

Bolting Flour for Pasta Making

I wrote (here) about the benefits of using freshly-milled flour to make pasta. In Cooking by Hand (2003), Paul Bertolli writes, “[f]lour used very soon after milling produces the best, most fragrant pasta.” To realize this potential, the pasta maker needs to consider the interplay of bran and gluten when making pasta. Bertolli recommends blending whole-grain flour with refined flour to mitigate the effect of whole-grain flour’s bran on the gluten fabric of pasta dough.  

Another way to reduce the impact of bran when making pasta with whole-grain flour is by bolting the milled flour. Bolting means passing whole-grain flour through a sieve to remove bran. This post generally explores bolting, introduces a bolting process that I use when making fresh pasta, and shares a pasta dough recipe that uses 100% freshly bolted flour.

Bolting Flour

Milling wheat berries produces whole-grain flour comprised of bran, germ and endosperm. A number of interrelated factors will determine the amount of material that bolting removes from whole-grain flour, including (1) mill-type and its setting, and (2) sieve-type and its specifications. Commercial millers employ sophisticated equipment to remove (or add) exact amounts of bran and/or germ from flour during the milling process. Home millers cannot match the level of precision of commercial millers. Instead, expect home bolting to catch material (i.e., bran, germ and/or endosperm) too large to pass through a sieve. Fortunately, this lack of exactitude poses few problems for a pasta maker if she takes a few precautions.

Successfully making pasta with home-milled, bolted flour depends upon an appreciation of the interplay among grain selection, mill settings and bolting equipment. Failing to consider these factors increases the likelihood of making a weak dough and pasta that breaks when cut and/or cooked. Although one can mask the impact of a weak dough by choosing a more forgiving pasta shape (e.g., creating cavatelli instead of making tagliolini or tagliatelle), knowing the interaction of grain, mill and sieve will help you to create the pasta you envision.

Grain Selection Because home-bolted flour will likely contain some amount of bran, knowing a grain’s protein content helps to understand how the dough will respond to different levels of bran and the likely elasticity and plasticity of the pasta dough. This information informs what type of pasta shape to make and how the pasta will taste.  For example, if I want to mill a soft wheat variety, such as White Sonora wheat berries (available from Hayden Flour Mills), I will bolt the flour with a series of fine sieves to remove more bran. Because soft wheat varieties contain less protein, removing additional bran helps to keep the pasta’s gluten fabric intact thereby mitigating the possibility that the pasta will fracture. 

I might also decide to blend soft wheat flour with a hard spring wheat or durum wheat variety with a higher protein content to increase the pasta dough’s strength. This decision allows me to make a pasta shape that might not be as successful if I only used a bolted soft wheat flour.

Mill Settings Understanding the exchange between a mill’s setting and bolting sieves also informs what you can expect from your flour and, ultimately, your pasta. 

I own a KoMo Fidibus Classic grain mill (here). By turning the mill’s grain hopper, I can adjust the mill’s grind from Fein (fine) to Grob (course). When bolting flour for pasta making, I keep the mill’s grind indicator set on the mill’s left miter joint. Grain milled at this setting and then bolted with the test sieves (described below) produces a fragrant, finely-textured flour.

Although it might seem counterintuitive at first, too fine a mill setting will produce a gritty flour because small particles of bran can pass through fine sieves. In my experience, a very finely milled flour, even when bolted through a No. 40 and No. 50 sieve, feels gritty when compared to a slightly coarser flour bolted through the same sieves. Because each mill is different, experiment with various mill settings and sieves keeping in mind that bolting a slightly course flour may result in a more refined (i.e., bran-free) finished flour.

Bolting Equipment I began bolting flour using a household OXO mesh strainer. Over time I invested in a No. 40 and No. 50 stainless steel test sieve made by Gilson Company. Both sieves measure 8-inches in diameter and are 2-inches deep (i.e., full height). The No. 40 sieve has an opening size of 425 micrometers and the No. 50 sieve has smaller openings of 300 micrometers. I decided to invest in a No. 40 and No. 50 after reading an aside in Marc Vetri’s Mastering Pasta (2015). He writes that farro flour bolted through a No. 35 sieve is “a little finer than semolina”. Armed with this knowledge I concluded that I could produce workable pasta flour using a No. 40 and/or No. 50 sieve. 

Through experience I know that 100 grams of wheat berries milled with my KoMo’s grind indicator set on the mill’s left miter joint and then bolted with my No. 40 test sieve will yield ±60 grams of flour. If I re-bolt this ±60 grams of flour through my finer No. 50 test sieve, I will catch approximately 20 grams of additional material resulting in ±40 grams of flour.

Knowing these extraction rates allows me to calculate the amount of wheat berries that I need to produce the desired amount of bolted flour with almost no waste of grain or excess bolted flour. But more importantly, I know through experience that flour bolted through a No. 40 sieve performs differently when compared to a more refined flour bolted through both a No. 40 and a No. 50 sieve. Because flour bolted through a No. 40 sieve will, based upon the flour’s grind, contain more bran compared to flour further bolted through a No. 50 sieve, the home pasta maker needs to carefully consider her grain selection, dough hydration and final pasta shape when using a 100% No. 40 bolted flour.

Armed with some basic bolting knowledge and through experimentation you can decide, by adjusting grain, grind and sieve, how you want your pasta to smell and taste. The universe of possibilities increases further if you blend home-bolted flour with a commercially refined flour to zero in on the characteristics that you want to achieve in your pasta. More on this in future posts.

Technique through a Recipe

Experimenting with your choice of grain(s), mill and sieve(s) provides the best instruction on how to mill and bolt flour at home to make fresh pasta. Here’s my process. I share weights, but keep in mind that the variables of grain and grind might yield very different results in your kitchen.

1) Place a medium-sized pouring bowl on a scale, tare the scale and put 330 grams of grain into the bowl. I recommend starting out with a high protein content grain. In this recipe I am using Bluebird Grain Farm’s Organic Methow Hard Red wheat berries.

2) Adjust your grain mill to a fine—but not its finest—setting. On my KoMo Fidibus Classic mill, I set the grind indicator near the top left mitre joint of the face of the mill’s housing.

3) Place a clean sheet of parchment paper (approximately 13” x 15”) on your work surface under the mill’s spout. The paper needs to be large enough to catch the flour that falls from the bolting sieve(s).

4) Put a full height No. 40 sieve on top of the parchment paper under the mill’s spout. Turn on the mill and add 330 grams of wheat berries. While the mill processes the flour into the sieve, replace the pouring bowl onto the scale, which should read zero.

5) After the mill finishes grinding the flour, lift the sieve with one hand and lightly tap the sieve against the heel of your other hand so that the flour moves back and forth across the screen’s face and flour gently falls onto the parchment paper.

As you bolt the flour, notice that the flour in the sieve will slowly change color and texture. The flour in the sieve will look darker as the screen retains more bran.

Also note the color of the collected flour collecting on the parchment paper. Stop bolting when the flour begins to slightly darken and the remaining material in the sieve is coarse compared to the bolted flour.

6) Pick up the parchment sheet on either side and carefully pour the sifted flour into the bowl on the scale. In my experience, 330 grams of wheat berries milled and sifted as described above produces ±170 grams of flour.

7) Replace the parchment sheet onto the work surface and put the full height No. 50 sieve on top of the sheet. Pour the ±170 grams of flour in the bowl into the sieve and replace the bowl onto the scale. Bolt the flour through the No. 50 sieve onto the parchment paper. Again, the material in the sieve will slowly darken as the flour makes its way through the screen, leaving bran and other material behind.

8) Carefully lift the sheet and pour the sifted flour into the bowl on the scale. You should have approximately 115 grams of flour. Adjust the flour to 115 grams by adding refined flour or removing sifted flour.

9) Add 1 whole large egg and 1 egg yolk (together weighing approximately 76 to 77 grams) to the 115 grams of freshly sifted flour. Knead by hand for 8 to 10 minutes until the pasta dough is smooth. The dough will feel quite firm during kneading, but will soften as it hydrates, wrapped in plastic wrap, for 30 to 40 minutes at room temperature.

It may take a while to get the feel of working with freshly milled and bolted flour. If you have experience making pasta with Tipo 0 flour, using the bolted flour shouldn’t be very different. The payoff from using freshly milled flour is a delicious pasta with a firm bite and heavenly aroma. To appreciate these qualities, simply dress the cooked pasta with a good butter and freshly grated Parmigiano-Reggiano cheese.

A quick note on cleaning the Gilson sieves. After pouring out the bran, I use a stiff brush to whisk the face and sides of the screens. After brushing you might still find small pieces of material lodged in the screens. Fastidious millers can use fine needles to clear away this detritus.

Home-milling opens up a world of flour possibilities to pasta makers. Take a look the grain offerings from Bluebird Grain Farm, Hayden Flour Mills and Montana Flour & Grain. I buy Kamut from Montana Flour and White Sonora from Hayden. Bluebird sells exquisite organic hard white and red wheat as well as einkorn.