Sour in an Hour? Brewers are experimenting with white koji to speed up the time to acidify their kettle sours.

[ryanmetcalf]

Has anyone tried using Koji to do a super fast sour? Didn't see any matches here on the forum when I did a search
https://en.wikipedia.org/wiki/Aspergillus_oryzae

Aspergillus oryzae, known in English as koji (Japanese: ニホンコウジカビ Hepburn: nihon koji kabi), is a filamentous fungus (a mold) used in Japan to ferment soybeans for making soy sauce and fermented bean paste (including miso), and also to saccharify rice, other grains, and potatoes in the making of alcoholic beverages such as sake and shōchū.

Came across this Beer and Brewing article that came out this week
https://beerandbrewing.com/sour-in-an-hour/

However, when you add koji into the mash of, say, a Berliner weisse, it will dramatically cut the time needed to properly kettle sour a beer.

“You talk to so many brewers who pitch lactobacillus (sometimes yogurt) on Friday, let it grow all weekend, producing lactic acid, and then come back on Monday to boil the wort,” says Bellomy. “With test brews that we’ve done with white koji, if you make it 20 to 25 percent of your grain bill, you could make a sour beer in a standard 1-hour mash time.”

It’s like the Fotomats of old: Sour in an Hour.

“White koji already contains the citric, lactic, and succinic acids, which impart a beautifully clean acidity to the beer,” Bellomy says.

Might be giving this a try here in early July

[LeighK]

Never heard of this method but please report back!

[johnpepin]

I'm very curious and might consider trying this method to sour a Berliner Weiss. Has anyone tried it? I'd appreciate your feedback?
Thank you,
John Pepin

[ryanmetcalf]

John, still haven't gotten to this, but sounds like I may end up being the first. Going to give it a try after the new year and holiday travels are in the rear view mirror.
I'll keep you posted! I've got a pH meter, so I can check it in intervals as it progresses, we could make charts!

Going to check and see if the Pan-Asia (Overland Park) stocks Koji, I can't imagine they wouldn't, the place is huge! Else I'll go Amazon if I can't procure locally, could test which brands are more effective than others

Pan-Asia Market
11940 Metcalf Ave
Overland Park, KS 66213
https://goo.gl/maps/D4b8VjUJVY4YMumT9

[johnpepin]

Did you attempt a koji brew?

[ryanmetcalf]

Bought the Koji, still haven't used it :/

[johnpepin]

I'm in the same boat. Probably do a 1-2 gallon batch and see how it goes first.

I did just pitch two different saison blends from Bootleg Biology. I have not used their yeast before so I anxious to see how it turns out. 10 gal of 1.060 sort of hoppy saison wort with 5 gals of saison blend yeast and 5 of saison parfait yeast. I've also got a batch of the funk weapon #1 that one of these will get as well as an addition.

Happy and safe New Years to you.

[ryanmetcalf]

Part of my issue has been reading/research, trying to figure out why their specific on the function/use. I keep getting caught up on the sentence,

“With test brews that we’ve done with white koji, if you make it 20 to 25 percent of your grain bill, you could make a sour beer in a standard 1-hour mash time.”

• So are they sizing it for the biological pitch count, at 20-25% of grain bill, you'll end up with enough fungi to do the work in an hour?
• Or is it a fixed addition of the already prepared Koji rice, like X lbs/% Acidulated malt?

Most Koji prep is in moist (not submerged/saturated) rice, so was wondering if there's a limit to using in the mash.

http://www.oct.co/essays/koji-beer-nuruk-mold

“The main thing that's tricky is you have to maintain a super specific temperature and humidity for the koji to do its thing,” he says. Most beer breweries don’t have the capacity to inoculate rice like that on a large scale.

But aside from temperature control, their biggest challenge is getting customers to understand what koji even is. Barnett recalls overhearing one of his employees trying to explain the new beer to friends.

“They asked ‘What’s a koji beer?’ and he said ‘I don’t know, some fucked-up shit,’” Barnett says, laughing. “I said, ‘No, no, no. Let me tell you the story of this ancient mold that achieves the same process of malting.’”

In the malting process, grains are sprouted and heated to develop enzymes, which then convert the grains’ starches into sugar. Koji also converts starches into sugars, but those catalyzing enzymes are generated by the fungus itself. This means that koji can be added to any starch to create sugar—not just grains.

In Korea, koji—known as nuruk in Korean—is added to a diverse amount of starches, including sweet potatoes, mung beans, wheat, cassava root, and of course—rice.

I mean, shoot, I'd even try wetting my grains, and mixing with the Koji, and leaving it all go for ~48 hours before doing a full/regular mash.

Other readings I found:
https://www.beeradvocate.com/articles/1 ... er-hybrid/
https://japanbeertimes.com/2014/05/rice-and-koji-beers/

[ryanmetcalf]

Ok, I might have re-read the Oct.co article again and caught this, they only used 10%. So the previous % might be for the rice dryness malt character mix, vs biological count

Over the last two years, he and his team have made two commercial batches with nuruk. First, they inoculated rice with nuruk, then they combined that rice with wheat to make a Berliner weisse. It was then dry-hopped with Equinox, Amarillo, and Cascade hops “to enhance the citrus aroma and flavor.”

“We use less than 10 percent of rice,” Kwan says. “Rice has a unique aroma but it is not what we want. So we use a small amount of it.”

For their second batch, they infused the sour with ginger, red pepper, and chrysanthemum. “We wanted to have the clear sourness from the nuruk and also have floral aromas alongside a unique gentle spiciness,” says Kwan.