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Bru'n water acid malt calcs

I’ve been using bru’n water with seemingly good results for a while now, but there’s one aspect of it that I’m a little unsure/skeptical of.

When I do very light beers, my water dictates that I need to add mash acidity to get pH where I want it, and my go-to method is to use a few oz of acid malt. What worries me a little is how controlled or well understood the amount of acidly is per oz of malt. Is there only one type of acid malt (My LHBS has Weyermann)…do they all have the same amount of acid (and what does Bru’n water assume)?

Should I just use actual acid to be sure?

Thanks for any thoughts or experiences on the topic!

The assumed contribution of acid malt is that 1% of acid mail will lower your pH by .1.

I would like to think that malting companies would have QC and would make sure their product is consistent. With that said being said, different companies could contain different amounts of acid. I do know that Weyermann claims the 1%=.1 pH drop.

I would pick one brand, testing it on a brew day (even with a pH meter) and stick with it so I know what to expect.

For the record, I just use lactic acid. With that Bru’n water has never been more than .02 off my target mash pH, which is close enough that I don’t even test for it anymore.

Agree with @loopie_beer, you’re taking a bit of a risk by assuming that the acid content of acid malt is consistent from batch to batch, let alone between companies. I don’t know how much variation there is, but it definitely is there. Using lactic acid will be much more reliable over the long run, unless you have a pH meter and are willing to measure it every brew day. Nothing against acid malt, it’s a good product. But you know exactly what you’re going to get with 88% lactic acid (or 20% phosphoric, etc).

Thanks, that’s kinda what I was thinking. A while back I thought–acid malt, that sounds easy, but based on the concerns above (and common sense :grinning:) I’m coming around to the idea that adding the correct amount of lactic acid is simple and seems more reliable.

I tried this out in Bru’n water and I notice that the mash pH prediction under the mash acidification sheet doesn’t change when I add acid on the water adjustment page. Seems like a bug and I think I can work around it easily enough, but odd…

Aha, I grabbed an updated version of Bru’n water and see it does not have the problem I describe above. Good to go!

Just out of curiosity, does anyone ever worry in the slightest about certain acids causing discernable flavors in their beer? Bru’n water claims that phosphoric is least likely to be perceptible, so I was probably going to go that route, but I suspect I’m worrying about nothing :slight_smile:

Sure, different acids certainly have a flavor threshold. I don’t remember what the thresholds are, and they will vary among different people. I’ve used too much phosphoric acid in a beer to where I could taste it in the final product. But I also have a lot of bicarbonate in my water. I try to use the minimal amount, and honestly haven’t had an issue with 88% lactic acid. I usually use in the ballpark of 10 ml or less, split between mash and sparge water and don’t get a flavor contribution. But others may notice it.

If you want to get fancy, you can split up your acid additions between different acids in an attempt to keep their concentrations below their flavor threshold. I think the latest paid version of Bru’n Water may support this calculation?

As @porkchop mentioned, there are flavor thresholds. If you find yourself having to add a lot of acid and exceeding the threshold consider cutting your water with distilled.

I’ve had an RO unit installed that is only used for beer. This way I can effectively build the water to suit per style.

I don’t necessarily want to get fancy :), but it seems like a good idea if you’re adding a lot of acid.

Just to make sure, does your 10ml rule of thumb refer to the actual acid, or the solution (I assume the former)?

The reason I ask is that I bought 10% phosphoric acid solution, and my water numbers indicate that I might need 20-30ml at that concentration. That would meet your guideline without a problem, right?

I evaluated the cost of acid malt vs 88% lactic about a year ago and posted my findings on the Bru’n Water Facebook page. I figured that acid malt was going to be much more expensive, but I was wrong. They have similar cost for similar acid contribution. So, that shouldn’t be a concern. The real concern that I have, and its voiced above, is the consistency of liquid lactic acid is much more assuring than the variability of acid malt strength. Acid malt users have reported that these products can have a strength variation of up to 100%. If you have a sack of acid malt and dial in its performance, its probably not a big deal. But if your LHBS has differing malt batches or maltsters, you could be surprised.

The supporter’s version of Bru’n Water does have the capability of employing differing types of acids in your brewing. That is handy when you have to neutralize a lot of alkalinity and you don’t want to incur the taste thresholds of some of the more ‘flavorful’ acids such as lactic and citric. But this should not put you off of using lactic acid. For those who had the opportunity to read my article on Bavarian Brewing water, I feel that all German styles (and many continental styles) should be brewed with some lactic acid since that is a minor element of those beer’s flavor profile. Don’t abandon lactic totally. Just keep it at the proper level and its an enhancement.

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Hang on, I didn’t mean to imply that it was a rule of thumb. I just stated that as a reference point, that with my water profile, and the styles I make, I don’t get any noticeable twang from 88% lactic acid. At least for the “clean” styles I occasionally make! YMMV. :beers:

Good enough, thanks. Reference point is a better description of how I’d use it as well. Don’t worry–I’m not planning to come away saying "porkchop told me to do X and it RUINED MY BEER :grinning: !!!1

For the record my water is pretty versatile and does not have a lot of bicarbonate. With a really light grainbill such as the Golden Strong ale I’m making, though, it does seem like some form of acid is the best way to get mash pH where I want it. If I were using 88% lactic on this batch, bru’n water indicates that I’d need 2.5mL in the mash, so I think I’m good.

With the 10% phosphoric that I have, though, it comes out to ~25ml in the mash mainly due to the difference in concentration, I assume. Seems like I should be fine with that as well. My question about the non-rule of thumb was intended to see if that number seemed OK or should make me nervous…

BTW–thanks for your insight, Martin, and for your wonderful product! It’s a fantastic product that makes a very tricky topic manageable.

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