Water chemistry in brewing is key and one important component to that is mash pH. While pH can be controlled to some degree with minerals, brewers tend to rely on acid to make significant reductions, the two most popular of which are phosphoric and lactic. In this xBmt, we investigate whether the type of acid used makes a noticeable difference. Results are in!
Good report by Brother Malcom. The moderate alkalinity worked in his favor. I have thought about doing a brew with my 298 ppm as CaCO3 total alkalinity water, but have thought that would be full of lactate flavor as it is twice as high as Malcom’s. It is too easy to just buy RO water.
Also, I’ve heard it mentioned before (maybe by Martin?) that some of the “expected” flavor profile of German lagers is due to the taste of Lactate. So levels at or near the detectable threshold, it may actually have a positive impact on certain styles.
I relate to Malcolm’s initial reaction. In fact, I purposefully sniff my bottle of lactic every time as a reminder not to overdo it.
However, as I type this I’m eating a salad dressed with olive oil and red wine vinegar. Sniffing the vinegar gives me a similar reaction. However, when combined at a reasonable level with other flavors it adds something that I might not be able to achieve otherwise.
Nice work guys – I love this stuff!
Yep, great writeup! Thanks.
I have only used 88% lactic acid to drop my pH. Makes it pretty easy with small amounts in 100% RO water.
Good write up. Thanks!
I think the results are no surprise. But much more than that, and/or the right style like Munich Helles, and/or a lactic sensitive taster and I think you’ll find a difference
The presence of lactate in German beers is widely reported in analytical reports for those beers. Lactate is also consumed to some degree by yeast. I have no idea what the metabolic products of lactate consumption by yeast is. But all of this does suggest that there could be a flavor impact to beer, even when the lactate content is below 400 ppm, which is the popular taste threshold reported for the average taster. Be aware that some tasters can perceive lactate at higher and lower levels…remember that 400 ppm is for the average taster.
I tried to estimate the water volumes used in the trial and came up with about 3.5 gallons of mashing water and 4.5 gallons of sparging water. Malcolm will need to confirm for me. At those volumes, the resulting lactate content in the overall beer is more likely to be around 250 ppm, not 400 ppm. Users of the supporter’s version of Bru’n Water know that that program reports the anion content of the various acids used and also warn when the content might be at or above the taste threshold.
The other concern I have is that the sparging water was only taken down to a pH of 6.0 and that suggests that the amount of alkalinity remaining in that sparging water is about 50 ppm (as CaCO3). I generally recommend bringing the alkalinity down to about 25 ppm.
All of these results do suggest that my original hypothesis that lactate can add a flavor ‘nuance’ to beers brewed with lactic acid…even when below the taste threshold of the average taster. I’ve heard some brewers say they hate even minor additions on lactic acid, but most drinkers seems OK with it. When sensitized to it, I expect that many tasters could detect it at lower than the average content.
I also speculate that likes and dislikes play into it. And that dislike may increase sensitivity. Someone who loves teeth melting sour beer may not detect or complain before someone who hates it.
Nice job! As usual, interesting results. Can someone please point me to a good explanation of all this p value stuff? Basically half of the people could ID and yet it is not significant?!
I am pretty sensitive to lactic acid and actually believe acid malt is superior to lactic acid. I’ve done the research and they are not the same. Of course, I have plenty of skeptics but that’s OK. I would love to see a side by side: acid malt vs lactic acid someday…
My only issue with acid malt is that there is no straight up pre-determined amount of acid on each lot of malt that is produced. I feel that this can vary too much for predicting a mash pH.
Other than Reinheitsgebot concerns, why would one use lactic over phosphoric? Is there something else I’m missing?
Have you had pretty big variations with it? I understand it might not be exact as liquid acid but I am not aware of problems. I stick to the Weyermann stuff and thought it was reputable. I am still primarily an ale brewer and prefer phosphoric acid for typical ales. Thanks to the great warm 3470 xbmt I plan to hit lagers much harder so I will be using acid malt more frequently now. If I get a new pH meter (#4) I can verify but I am really enjoying brewing sans meter and just using BNW. I tested BNW extensively with my last meter and was quite pleased with the outcome.
Another option is CRS (carbonate reducing solution), which is what brewers use in the UK to reduce alkalinity in hard water. It’s a mix of H2SO4 and HCL so it increases sulphate and chloride levels slightly without introducing any other unwanted minerals. More effective that gypsum.
I like the idea of CRS. However, the fixed proportions of sulfuric and hydrochloric acids can end up pushing the beer flavor into the “minerally” range. The main problem is that CRS adds almost as much chloride ion as it does sulfate ion. We are better off tailoring the addition of either acid to produce a better result.
I’m a long way removed from stats class, but in layman’s terms the p value for these experiments is the odds that the results could be merely due to random guess. The lower it is, the more likely to be a significant result. They use a p value of .05, which basically amounts to a 5% chance it could be random guess or 95% confidence that the results are significant.
Remember, this is a triangle test so you’d expect 33% to be right, on average. Above that, and it is more likely to not be due to random chance. The actual calculations are where the statistics comes in, to determine how many positive results you would need from a given sample to hit a particular p value.
Great summary. I started typing a response last night and mine became so convoluted that I just discarded it 
Since this one was “in the neighborhood” of significant he did include the preferences, which I also thought were interesting. Of the 11 people that successfully selected the odd beer out, only 4 selected the phosphoric acidified sample as the beer they preferred. 5 had no preference, 1 preferred the lactic sample and 1 could no longer tell the difference (not sure how that happens).
Keep in mind that p value is not the be all, end all…it’s merely a sign that further investigation is warranted. We discussed this with Marshall the last time he was on the podcast to talk about one of our experiments. Here something to look at …http://www.stats.org/mismeasure-scientific-significance/ and
As noted, I don’t think the lactate content in those beers would have been high enough to create a notable taste difference. The resulting scatter in the preferences should not be surprising. If the tap water had been a bit higher, I do believe that the tasters would have picked out the lactic acid more reliably.
I pretty much agree, but everything depends on what you’re brewing and where you want to end up. CRS is just another tool to have in the toolbox. For certain beers I can use CRS and nothing else and hit mash pH and mineral targets with tap water. In other cases I still resort to dilution with soft water or using gypsum etc.
Yes, the key thing is not to confuse evidence and proof. A significance test provides evidence, not proof. Scientific experiments can’t prove a theory is true. Strictly speaking none of the exbeeriments has proved anything, but there’s enough evidence to change the way we brew in some cases.
A big problem in science is “p-hacking” - cherry-picking trials that return significant results and not publishing the non significant ones. Hence the importance of transparency and being open with results however disappointing/unpalatable they are.