In his book, Brewing Science and Practice , Dennis Briggs notes the optimal mash pH may be different depending on the desired outcome. For instance, according to Briggs, if the focus is solely on saccharification, a mash pH bet 5.
To evaluate the differences between a beer made with a notably low mash pH and the same beer made with a mash pH accepted to be in the normal range.
Two days prior to brewing, I made a giant liter starter with 2 packs of WLP Southern German Lager yeast, the volume determined by my preferred pitch rate calculator. I began preparing for brewing by collecting pure RO water the a day ahead of time.
I measured out and milled the grains for both batches as the strike water was heating. Each batch was mashed in and settled at the same target temperature. I took pH readings at 15 minutes into either mash and found the low pH wort was at pH 4. After each mash finished a full 60 minute rest, I proceeded to collect the full volume of sweet wort using the no sparge method. Both worts were boiled for 60 minutes with hops added at the times listed in the recipe.
Out of curiosity, I pulled samples for pH measurement from the worts as they neared the end of the boil and noticed both experienced a very slight drop. At the conclusion of each boil, the wort was rapidly chilled to slightly warmer than my currently chilly groundwater.
Hydrometer measurements at this time revealed the low pH wort achieved a slightly higher OG than the normal wort, which went against my expectation that low pH would hinder mash efficiency. Left: low pH 1. I racked the chilled wort to corny keg fermentors and placed in my cool chamber to finish chilling down to my target fermentation temperature. After decanting the supernatant from the cold crashed started, I split and pitched equal amounts into either fermentor.
I also added 10 drops of Fermcap-S to both batches in hopes of staving off a crazy blowoff. The beers were both happily bubbling away when I checked on them 24 hours later. Subsequent hydrometer measurements taken over a few days 3 weeks later confirmed FG for both batches had been reached. Interestingly, the difference in FG between the batches was similar to the difference in OG, making me wonder if perhaps low pH encouraged increased extraction of unfermentable sugars.
I took final pH readings at this point and was quite startled to find out that both had settled at a very similar spot. With the beers finished fermenting, they were pressured transferred to serving kegs then cold crashed, fined with gelatin , and carbonated.
When it came time to present the beers to tasters for evaluation, both were clear, carbonated, and looking quite tasty. A panel of 22 people with varying degrees of experience participated in this xBmt.
Each taster, blind to the variable being investigated, was served 2 samples of the normal pH beer and 1 sample of the low pH beer in differently colored opaque cups then instructed to select the unique sample. These results indicate tasters were unable to reliably distinguish a beer produced with a lower than recommended mash pH from one produced with a normal mash pH.
A difference of pH 0. Putting it this was makes the results of this xBmt, that tasters were unable to reliably distinguish the low mash pH beer from the normal mash pH beer, a tad more more interesting. Not only did a beer that had 19 mL of lactic acid added to the mash taste the same as a similar beer without acid, but they ended up at nearly the same post-fermentation pH, which supports the idea that yeast stops working once beer pH is outside of the optimal range.
This might explain why the low mash pH beer finished with a higher FG, the yeast simply puttered out once the pH floor was hit, suggesting fermentation serves as an equalizer or sorts. If the observed differences in OG and FG between the batches are are indeed a real function of the variable, it provides evidence that extraction may be negatively correlated with mash pH, whether it effects flavor or not.
Interestingly, every prior water chemistry xBmt that achieved statistical significance involved differences in mineral composition. If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below! All designs are available in various colors and sizes on Amazon! If you enjoy this stuff and feel compelled to support Brulosophy. Thanks for another great article. This confirms to me that, while mash pH is important, you can get away with some mistakes.
With my first ever AG brew I attempted to get my head around water chemistry and failed. I ended up with a pH of about 4. The mash went fine but the beer finished quite a few points higher than the expected FG.
Wow, very weird. Do you have any idea what the mash conversion efficiency was on the two batches? I had anecdotally been thinking that my beers that had accidentally gone up closer to 5. Anyway, I wonder if the yeast is able to adjust the pH of the wort to its desired pH within reason?
Not trying to anthropomorphize yeast, just offer a suggestion for why the final pH was similar. It seems like the final pH being the same would result in the same flavor UNLESS the anion from the acid chosen has a strong flavor component eg lactate from lactic acid, phosphate from phosphoric acid, sulfate from sulfuric acid, chloride from hydrochloric acid or unless flavors are extracted from the mash at different pHs.
I am looking forward to your high pH version! In my experience, the FG has very little to do with the mouthfeel of a beer unless you really ferment it down to super low levels using enzymes or unless there are simple sugars left which taste sweet and give the impression of a thicker beer. I think things are becoming more muddled, confusing and unknowable rather than more clear with some of these results.
I agree. It IS nice to know that you can screw up a lot of things on a beer, and it has a good shot at turning out just as good! The checker by Hana was annoying, constantly had to manually calibrate it. The final pH reading is using my new thermoworks meter, auto calibrates, been awesome so far.
Just wondering. I have the which I love, think Marshall has that same model. A few of the other writers have the which I believe they like but can speak to it.
The auto calibration on the is so great. This product will automatically lower, or raise, your mash to 5. All you do is add it to your mash tun, and it does the rest. Mash stabilizer is a very easy product to use that eliminates the need to use pH Strips or a pH meter. There also is a technique called an ""acid rest"" which can be employed to lower the pH of the mash by varying degrees. Homebrew Con, Minneapolis, MN, Hopkins and B Krause.
Biochemistry Applied to Malting and Brewing. Mettler Toldeo, Homebrew Con, Portland, OR, Topic: Controlling pH. Take a closer look at pH throughout the brewing process. Brew-in-a-bag BIAB continues to grow in popularity around the world. Learn from two brewers well versed in maximizing the BIAB experience.
Log In Support Cart 0. Search for: Index. Standard Practice? Most recommendations to brewers state that mash pH should be 5. But when one digs deeper, the numbers are anything but simple. Photo courtesy of Shutterstock. This website uses cookies to improve your experience. You can opt-out if you wish. Accept Reject Read More. Close Privacy Overview This website uses cookies to improve your experience while you navigate through the website.
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