Rice protein impacts on Sake

Rice protein impacts on Sake

I am looking at a paper, which in part, discusses the impact of rice proteins on sake aroma and flavor. And admittedly, I may be stepping over the boundary between sake brewer and geek with this discussion, but I think you may find it interesting to see some of the underlining interactions that make sake what it is.

In this paper1 the authors brewed five sake variants, four of which include rice enriched with rice derived proteins. They then assessed the relative impact of these proteins on flavor and aroma.

The protein in the rice consists of roughly of 20% prolamin and 70% glutelin with several other proteins filling out the mix. The four tested in this study were prolamin, glutelin, globulin (2% each of total rice mass enhancement) and albumin (1% total rice mass enhancement). Continue reading “Rice protein impacts on Sake”

  1. Influence of Rice Proteins on Eating Quality of Cocked Rice and on Aroma and Flavor of Sake by Sachiko Furukawa, et al. 2006

Time for shibori ( 搾り)

Description of the sake pressing process (shibori).

After the moromi (main ferment) has come to the stage where the ferment has run its course or it is time to stop it from going any farther, it is time for shibori; that is the pressing or squeezing of the moromi to separate the lees from the sake. This is mainly done in three different ways in kura (breweries) today and probably more ways than Sunday by homebrewers.

The most common way to press is to use a machine called Assaku-ki often referred to as a Yabuta; the name of the main supplier of assaku-ki machines. The moromi is pumped into these machines where it is squeezed by an air bladder to force the sake through a fine mesh that holds back most of the lees. As the lees build up on the mesh more and more of the lees are held back because the lees themselves become a part of the filter. In the most common configuration, the filtering action is so good that it filters out the yeast as well as the lees and hence stops all further fermentation. Continue reading “Time for shibori ( 搾り)”

John Gauntner’s Sake Professional Course

Describes John Gauntner’s Sake Professional Course and how I liked it.

This past week I attended John Gauntner’s Sake Professional Course (SPC). I had a very good time both in class and with the other participants at the Izakaya’s outside of class. The class is three days of non-stop sake information loaded with special little stories that only someone who has spent a long time in the industry and with the many kura could have accumulated. I expected the course to be focused on, well training Sake Sommelier, over my own interest in Sake Brewing. I was not disappointed in this expectation but the course was more than just for the Sommelier.

The 46 attendees were from four major categories: the restaurant business, distributors and distribution channel, individuals with a special interest in sake and sake brewers like me. The interactions between these interests were mostly complementary and enhanced the overall experience and learning. Continue reading “John Gauntner’s Sake Professional Course”

Making Koji for Sake

Making Koji for Sake

In order to make koji for brewing sake we need to go through the same steps that we do to prepare rice for brewing sake. In fact, it is often the case that a portion of the rice goes directly into the brewing sake while another portion is used for koji. So, as always we begin by washing the rice. This is to remove all contaminates, including the powder (Nuka) that remains after milling and any material added by the miller, like iron. Removing the nuka lowers the stickiness we will have after steaming. And, as mentioned elsewhere, iron is very bad for sake as it darkens the sake and speeds a reaction of residual sugars with amino acids that harms the flavors and aromas.

Washing the rice is followed by steeping the rice until we reach the desired water uptake level, usually between 25% and 35%. If the uptake of water is too little the rice will not steam properly leaving a hard uncooked center that the koji mold will not penetrate. On the other hand having too much water uptake will cause the rice to be too mushy and sticky after steaming. This results in a base that is too easy for the koji mold to penetrate and this prevents or lowers the production of transformative enzymes we want. Most rice used for hombrew sake will need to steep between 30 minutes and two hours. As homebrewers we are more often than not more guilty of soaking too much than too little. Continue reading “Making Koji for Sake”