NEM - Low ABV Idea

[jujitsudave]

Been reading about Non Enzymatic Mashing for low ABV beers. Basically cold steep the grains overnight with a BIAB, drain, pour off the liquid from trub, boil etc.

My idea(s): adjust the pH to 3.9 after pulling the BIAB, add hop extract to achieve the needed IBUs (similar to Flash brewing), pitch yeast and do a no boil.

The boil is presumably needed to pasteurize the wort snd isomerize the hops. But if you get the pH low from the start, and use hop extract (rho), then presumably this is unneeded? I think it would even be feasible to add acid malt to bring the pH to 3.9 during the mash.

Thoughts?

 

[BrewnWKopperKat]

Been reading about Non Enzymatic Mashing for low ABV beers. Basically cold steep the grains overnight with a BIAB, drain, pour off the liquid from trub, boil etc.

My idea(s): adjust the pH to 3.9 after pulling the BIAB, add hop extract to achieve the needed IBUs (similar to Flash brewing), pitch yeast and do a no boil.

an all-grain 10 minute brew day? Doubtful

One of the videos I referenced in Flash Brewing'? This looks interesting! (probably BeerSmith podcast #309) explains the though process that got them to custom yeast, custom DME, and newer hop products. Take some time to listen to the videos - as it will give you additional things to consider.

If you look at the Low Enzymatic/Cold Mash/Low alcohol beer, you'll find many people who found moderate success with the cold extraction process. Initially, it was a novel process, now it's probably just a novelty. I paused using it as it was took more time than I wanted to spend on a brew day.

With regard to fermenting a cold extracted wort it's up to you to decide if the risks are worth the reward.

Thoughts [on the process]?

IMO, too short and too shoddy.

 

[Agent]

My gut says that even with RO, you may be well above the lactic taste threshold to hit 3.9. Not to mention water isn't well buffered at that point, so it may be easy to miss your mark dramatically.

Edit to add that I think the boiling/pasturizing is needed to kill off bacteria and fungi, whereas the low pH is specifically needed to prevent botulism formation later. Which is why open juice in the fridge can still spoil despite very low pH.

In addition, I'd be worried about proteins normally pulled out from cold/hot break formation.

 

[BrewnWKopperKat]

... then presumably this [a boil] is unneeded?

There's a recent (and active) thread over at Brewer's Friend forums: Is it essential to boil wort? with some information on why a boil is needed.

 

[jujitsudave]

Thanks everyone. Looks like I will need to rethink my approach.

Maybe do a concentrated NEM and then a hold step at 175 F for 30-45 min. I can then dilute with pre-chilled RO water.

I've been thinking about methods to go the extract route as well, in case anyone has feedback on that.

Depending on the beer style, was thinking of using an amber DME and then a little bit of malto dextrin. Add only enough DME to a achieve less than 0.5% ABV, and then use malto dextrin to ensure a desired final gravity that restores mouth feel and body (FG 1.005-1.008 is my current preference). Given the very little amount of DME needed, I'm leaning towards amber DME to help retain color and a little bit of malt flavor as well. Although I guess I could also cold steep some specialty malts for this too.

Trying to find any ways of shortening the brew day. Mashing, boiling, and cooling are by far the longest steps. Right now I get up at 4 am just to squeeze an all grain batch in before the kids wake up.