Sparge for non-enzymatic mashing (cold mashing)

TravisStoon

I've been experimenting with low-alcohol beer using non-enzymatic or cold mashing. I do this using brew-in-a-bag and am not sure what to do about sparging. I've been getting good results with just hanging the bag to allow it to drip (I let the starches settle for a few hours and let the bag drip during that time). I'm certain I could get more extraction by squeezing or sparging with water, but I'm afraid of raising my fermentable:non-fermentable extract ratio.
Has anyone done any trials? Or better yet, taken some data?

VikeMan

I haven't done this, but I'll speak theoretically. I can't think of any reason that squeezing the bag or sparging with (cold) water would have any impact on fermentability. For it to be so, there would have to be some phenomenon whereby fermentable sugars cling to grains more than other gravity contributors.

TravisStoon

This is a big part of the NEM process: you try to extract the non-fermenatables while leaving behind the ungelatinized starches.

doug293cz

Starches, gelatinized or not, are not fermentable, unless you use a yeast with diastatic power of its own. Starches in the beer will cause haze, and also will be an issue for those with diabetes. Squeezing will not separate non-gelatinized starch from the grain, but may release more gelatinized starch into the wort.
Brew on

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BrewnWKopperKat

In the five or so years that I've been reading about cold extraction and occasioanlly brewed with cold extraction, I have yet to read about a fermentable:non-fermentable extract ratio. Most of the content has been either original (HomeBrew Con presentation audio/video, content at Briess' site, ...) or people writing about their experiences based on that content.
What is the fermentable:non-fermentable extract ratio? why does it matter? and how does one measure it in the real world to confirm the estimates?
If the process is producing good wort, I don't see a problem that needed to be fixed.

TravisStoon

There are enough enzymes in the cold wort that the starches are converted as you heat through the saccharification temperature range on your way to the boil. I regularly do iodine tests to confirm this.
Dan Bies talks a lot about this in his seminal NEM presentation. He doesn't explicitly mention this ratio, but the whole thing is about increasing non-fermentables while decreasing fermentable sugar. If you look into the scientific literature, they usually normalize the fermentable and non-fermentable extracts by the total extract, which is related.
Why? This allows you to have a fuller flavour low-alcohol beer without increasing the alcohol percentage (or a extremely malty beer at moderate ABV).
In a homebrew setting, you could get an indication of this via your attenuation. If you use a highly attenuating yeast under ideal conditions, it will convert all the fermentable sugars while leaving behind everything else. If you use your actual yeast, you'd get a more specific value of what is actually fermented (out of the theoretically fermentable sugars). I'm currently doing a forced ferment test (incubate small sample at 27 C) on both my first and second runnings to do exactly this. Should have the results shortly.
Yeah, it's not a huge problem but the process seems very wasteful and if I can improve my efficiency with little downside, I'll do it.

TheMadKing

Have you tried mashing at 200F? I have zero experience with this, but that would seem to be the most efficient way to neutralize all enzymes very quickly from the get-go and result in a highly unfermentable wort. Just spitballing though

TravisStoon

Yeah, high temperature mashing is another method, which I haven't tried yet.
There are lots of approaches to low alcohol beer, but I don't want to get too far away from the thread topic: sparging with cold-mashing.

BrewnWKopperKat

Link?
This [fermentable:non-fermentable extract ratio] is starting to feel like an extension to the 'original' cold extraction process.
If you can share links to what you're reading in the "scientific literature", that may be interesting and/or helpful.

TravisStoon

Bies at Briess:
Non-Enzymatic Mashing : Why do it? - ppt downloadNon-Enzymatic Mashing : Why do it? BLOW YOUR MIND NEW MALT FLAVORS!! The Biggest Reason? BLOW YOUR MIND NEW MALT FLAVORS!!slideplayer.com

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Dan Bies, Author at Brewing With Briesswww.brewingwithbriess.com
Sample Papers (there are lots out there):
Dalberto, Gabriela, et al. "Cold Mash in Brewing Process: Optimization of Innovative Method for Low-Alcohol Beer Production." ACS Food Science & Technology 1.3 (2021): 374-381.
Schöttke, Niklas, and Frank Rögener. "Cold mashing-Analysis and optimization of extraction processes at low temperatures in the brewing process." E3S Web of Conferences. Vol. 247. EDP Sciences, 2021.
Edit: misspelled Bies or Briess

doug293cz

Good point. I didn't think about that.
Brew on

BrewnWKopperKat

Good point. I didn't think about that.Click to expand...That idea also shows up in this topic (from back in 2019): Low Enzymatic/Cold Mash/Low alcohol beer
Some brewers were getting very low (around 1%) ABV by going directly to a boil; others were getting around 3% by heating to 150F-ish and resting for 30 to 60 minutes.

BrewnWKopperKat

Link?Click to expand...Bies at Briess:
https://slideplayer.com/slide/12403228/Click to expand...There is also a HomeBrew Con 2016 presentation (slides + audio) and a PNWHC17 presentation (link to PPT here; if the page/PPT is 404, use Internet Archives). The transcript associated the "slideplayer" link you provided has some information that's not in the HomeBrew Con 2016 presentation. And the HomeBrew Con 2016 presentation has some information that's not in the other slide decks.
Thanks for the references to the newer (2021) papers.

BrewnWKopperKat

Background: For those curious about cold extraction, the topic I mentioned earlier (Low Enzymatic/Cold Mash/Low alcohol beer) is a good starting point. It's a combination of discussion and live links to what people were reading. There's also a link (- Alcohol Free and Ultra Low Beer Brewing Techniques) to a site that covers a number of different techniques for making low ABV beer.
Back to the original topic.

I've brewed with the technique a number of times (BIAB with or without sparging). For me, a course grind (don't double mill), no sparge, and gravity (let the wort settle before transferring to the kettle) worked best for getting a good wort.
If the goal is to produce low ABV beer, whether or not to sparge may be the wrong question.
When compared to other low ABV techniques, cold extraction requires an extra step which requires extra time and equipment. There are likely to be additional disadvantages when brewing larger volumes and water / wort flow is fixed.
Additional uses for cold extraction were mentioned in (each of the three variations of) the seminal presentation. I tried one of those techniques once recently. The result was a good beer. I may get back to it with a side by side comparison in the future.
Brewing szience can be interesting. The results from pragmatic techniques is even more interesting.
As I mentioned above, there are a number of suggested uses for cold extraction. AFAICT, only low ABV beer has been explored at the home brew level. I'm not against the technique, but if one is looking to optimize a brewing process for low ABV beer, cold extraction may not be the best starting point.
It would be interesting to hear of commercial breweries that are actively using this technique.
Has Zymurgy, BYO, or CBB published any recent (2021, 2022) articles on the technique or on commercial breweries that actually use this technique? I'm aware that BYO did a technique comparison article a couple of years ago.

TravisStoon

Fast ferment tests results are in!
I did a forced fermentation at 27 C on about 200 mL of both the unsparged wort and the runnings after a dunk sparge. I didn't do this as carefully as required, and there are some precision issues with the low gravity. The first runnings had a real attenuation of 49% when measured using a hydrometer and 27% when using a refractometer. The sparged runnings were 55% and 60% respectively. The OG of the two samples weren't exactly the same, but if I scale them to compensate I get 0.65% ABV for the first runnings and 1.4% for the sparged.
I terms of extraction, I got about 11 L of first runnings at 1.028 and about 4 L of sparged runnings at 1.015, so I could increase my total extract yield by roughly 19% by doing a dunk sparge, but at the cost of increased ABV.
I did taste this hot-fermented beer and it tasted pretty decent with none of the obvious off-flavours you usually get. I'm guessing that the low ABV allows the yeast to work at a higher temperature with reduced stress. Might be something to look into later.
All of this is very rough, with a lot of sources of error. I'll probably do this again and be more careful next time I brew.