Monday, February 16, 2009

Let's mash like it's 1799!

We finished mashing the remaining eight tubs on Friday and Saturday and introduced the yeast. "Mashing" is the process of mixing and cooking the grains in order to change their starch into sugar -- which is what the yeasties then will consume (ferment) in three to five days to produce alcohol. The process is essentially the same whether you are producing 100 gallons of spirit in two weeks like we are, or thousands of gallons a day like at the large commercial distilleries. But instead of using giant vats with lots of modern equipment to speed things up, our little tubs accommodate only 120 gallons and the process is strictly by hand.
To guide us, we have several recipes and detailed descriptions of mashing that we've found in distillling manuals that were published in the late 18th and early 19th centuries. But Dave P. has some modern insights and tricks to bring to the table as well. When working with wooden mash tubs, bacterial contamination is a real problem, and the last time we tried distilling about a year ago this was a major obstacle. In addition to doing our best to clean out the tubs, we painted their interiors with a lime slurry to lower the PH level (making it less hospitiable to bacteria). Dave also has taken the precaution of adding hops to the water as we boil it, as this releases a natural anti-bacterial agent.
As for the mashing itself, it is a time consuming and arm breaking process that requires lots of attention to detail. Here are the steps: (1) about 15 gallons of cold water is placed in the tub, followed by 15-20 gallons of boiling water -- enough to bring the temperature up to 13o-140 degrees; (2) the ground corn is carefully added, while a second person vigorously stirs using a wooden mash "rake" -- the stirring is needed to help the grain dissolve and to retard clumping into balls of dough; (3) after the corn is in, we fill the tub two-thirds full with boiling water and let it sit for 20 minutes -- allowing time for the corn starch to become gelatinous; (4) add the rye, stirring vigorously -- this is the hardest work for the stirrer as the rye gelatinizes almost immediately, turning the solution into a thick soup; (5) keep stirring occasionally, waiting until the temperature cools to about 148 degrees -- the optimal temperature for malting; (6) stir in the malted barley -- the barley helps to break down the starch even more, making the mixture much thinner and easier to stir; (7) keep stirring, letting the temperature drop to about 90 degrees, at which point we add the yeast; (8) take a break and rest your arms, before starting on the next tub!


  1. Hi,
    That's a lot of stirring, I was just wondering
    If your mash is at less then 160 degrees after you add your rye, if so shouldn't you be able to add a small amount of your malted barley to make stirring a little easier?
    as alpha-amylase works at up to 160 degrees.


  2. Hey,

    Dave P. agrees, and we kept that open as an option. But the viscosity never got to the point where it was a real hindrance, so we never had to do it.