In the 27th and first episode of season two of the Japan Distilled podcast, your hosts Christopher Pellegrini and Stephen Lyman tackle the sticky topic of the difference between malt vs. koji when it comes to breaking grains down into fermentable sugars.
Mixing and Editing: Rich Pav (https://www.uncannyjapan.com/)
CHRISTOPHER PELLEGRINI Vermont born and bred, long-time Tokyo resident and author of The Shochu Handbook, Christopher learned about delicious fermentations as a beer brewer at Otter Creek (Middlebury, VT). He now spends most of his waking hours convincing strangers that shochu and awamori are unlike anything they’ve ever tried before.
STEPHEN LYMAN discovered Japan’s indigenous spirits at an izakaya in New York City. He was so enthralled that he now lives in Japan and works in a tiny craft shochu distillery every autumn. His first book, The Complete Guide to Japanese Drinks, was nominated for a 2020 James Beard Award.
Stephen and Christopher are fans of well made spirits whether they’re malted or kojified.
If you have any comments or questions about malt vs. koji, please reach out to Stephen or Christopher via Twitter. We would love to hear from you.
Malt vs. Koji
Early on in the introduction of Japanese alcohols to the west, an unfortunate translation happened. Rice koji (米麹) was translated into “malted rice” … the mistake was certainly an honest one, but it was also factually incorrect. Malting and koji saccharification serve the same purpose. Despite both leveraging natural processes to extract reluctant sugars from grains, their methods are startlingly different. In this episode we attempt to untangle these approaches to alcohol production.
Malting is most commonly used in beer and whisky production. Malting is the process of tricking whole grains into germinating. This beginning of the germination process activates enzymes that release sugars in the grain to provide food to the germ, which will grow into a plant. However, once those sugars are enzymatically released, the process is shut down by drying and heating the germinated grains, which are then called malted grains.
While most beer brewers do not make their own malt, some malt whisky makers do still malt their own grains. Floor malting is the most traditional method.
We are committed to making kojify a verb so we will keep using it until we hear others do the same. This is the process of converting the starch in a grain or other substrate into soluable sugars using koji mold. In Japan, once you’ve grown koji mold on rice it’s no longer considered rice. It is now something else. It’s rice koji.
Unlike malting, which relies on the grain’s own enzymatic activities to saccharify the starches, kojifying uses the mold’s enzymatic activity to do the work. In order for koji to innoculate the grains, they need to be polished before being steamed. This is distinctly different from malting, which relies on whole grains.
Besides the obvious difference of germination vs. mold propagation between malting and koji, there are also differences in the brewing process. For malt brewing, the sugars are extracted from the grains, the spent grains are disposed of, and the yeasts are introduced to the sugars in a process known as multiple sequential fermentation.
For koji alcohol, this process is a bit different. Both the rice (or barley or sweet potato or buckwheat or corn) koji and yeast are introduced into the same fermentation vessel simultaneously in a process known as multiple parallel fermentation. In this case, the koji continues to break down the starches remaining in the grains while the yeasts begin converting those sugars into alcohol. The koji will also continue to do this process to any new grains or starch sources introduced to the fermentation as is common in shochu production.
Much More to Explore
These show notes just scratch the surface, but should serve as a useful aid as you listen to the episode itself. As always, please feel free to reach out if you have any questions about malt vs. koji.