Low ABV: cold mash vs hot mash

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Which one do you prefer?

  • Hot mash

    Votes: 4 100.0%
  • Cold mash

    Votes: 0 0.0%

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    4

Plop

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After reading a few threads about low ABV beers I decided to take a bash at it. I was not sure regarding the process, there are 2 ways: cold vs hot mash. I tried both and I thought some people might find the results interesting.

My goal was to compare the 2 processes from a practical standpoint and, of course, for taste.

The recipes are not fancy at all, I tried to make them as close as possible to be able to compare the result of each process. I used the ingredients that I had available at that time: base malt + crystal + US-05. You will see that I use a lot of hops but my hops were old and my utilization is pretty low so I decided to put much more than what the other recipes I saw use.


Hot mash
Screen Shot 2022-04-05 at 4.27.20 PM.png


Recipe: Brewfather
Based on Lallemand's best practices: https://www.lallemandbrewing.com/wp...AL-bestpractices-Low_alcohol_beer-DIGITAL.pdf

Fermentation:
Screen Shot 2022-04-05 at 4.39.40 PM.png


As expected, the fermentation was really slow. The yeast struggled to get going. Brewfather was able to estimate the FG pretty well and it is quite high (it does not taste sweet at all though).

Brew day went well, no surprise since it is the same as a regular mash but with a higher temperature. It makes it easier to reach boiling temperature once the mashing is over.

Even after a few weeks of laggering, the beer would not become clear, not sure why.
The aroma is bland, like a light beer. The taste is somewhat fruity, maybe the struggle during fermentation pushed the yeast to produce some esters. It tastes a bit thin, slightly watered-down but it is closer to a standard beer than the cold mash.

Cold Mash
Screen Shot 2022-04-05 at 4.27.14 PM.png


Recipe: Brewfather

Fermentation:
Screen Shot 2022-04-05 at 4.57.29 PM.png

Brewfather expected an ABV of 1.6% but I just got 1.1%. The fermentation started quickly and was pretty fast, that being said it was a small batch (3 gal) and I reused the yeast from the hot mash.

I thought that one would be easier as the mash happens more or less overnight but nope... I saw a few people struggling with scorching, I was really careful when transfering from the bucket + bag to the kettle and left as much flour as I could in the bucket. It didn't matter, it was scorched enough for the kettle to need a thorough cleaning but not badly enough to make the beer undrinkable. Take that with a grain of salt though, I had an issue with my grain mill and I had to crush the grain twice, that might have made more flour than normal.

Of course, it took a while to go from fridge temperature to boiling, that might have contributed to the scorching? Recirculating the wort might help?

This one got clear in a week. The aroma is really malty, like a bitter, the flavours are not there though. It tastes like a bery watered-down English bitter, which is not too bad for that level of alcohol.


A few thoughts

It is hard to compare the 2 beers as my cold mash did not go as planned because of the scorching.
I suspect that the beer would have been terribly bland if I hadn't scorched it and it has a low FG which probably caused that significant thiness.

The hot mash was, overall, easier to manage and tastes closer to a normal beer than the cold mash. I will try again that technique with a saison that will use different grains and adjuncts, that should be a much better style for a low ABV beer.
 

BrewnWKopperKat

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A couple of general observations.

In other threads, people are able to brew using "cold mash" / "cold extraction" without scorching and without a "grainy" taste that occurs when double crushing and using BIAB.

There a number of approaches to low ABV beer. "cold mash" / "cold extraction" is the most labor intensive of the three.
 

CascadesBrewer

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After reading a few threads about low ABV beers I decided to take a bash at it. I was not sure regarding the process, there are 2 ways: cold vs hot mash. I tried both and I thought some people might find the results interesting.

Great experiment and thanks for reporting. What is your boil equipment? Propane? Electric element? Stove?
 

BrewnWKopperKat

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What is a "cold mash"?
It's similar to a "cold steep". Base malts are included in the "cold mash".

The process is also known as "cold extraction" as the process extracts flavors, colors, enzymes, and some fermentable sugar.


Extract efficiency is around 25% (vs 75% for a normal mash). People report very low ABV when heating the wort directly to a boil. Others report 3-4% ABV when heating the workt to 150F-ish for 30-45 minutes, then continuing to a boil.

This topic "Low Enzymatic/Cold Mash/Low alcohol beer (link)" here at HomeBrewTalk contains a lot of information from a number of people who have used the technique a number of times.
 

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