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Category: Brewing Tips
Tags: beerbrewingexperimentsflavorpH
Entities: ABS HomebrewAtlantic Brew SupplyBrewlosophyJohn PalmerMalcolm FraserMatt Skillstad
00:00
monitoring and adjusting Mash pH is something most Brewers are familiar with but is a step that many let fall by the wayside how much does pH in beer really matter well to find out John Palmer has generously agreed to take us through his presentation on ph in beer and trust me
00:17
there are a few gems in here I for one learned that I've been using my pH meter wrong the whole time then in true brulosophy style we're going to take the theory and put it to the test into experiments what is pH why does it
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matter in beer and can blind tasters detect a difference let's get into it this episode is sponsored by ABS Homebrew more on them in a bit hi I'm John Palmer the author of how to brew and the water book now before we get
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into the impact of pH in Brewing it's probably a good idea to briefly Define what PH even is pH is a a really interesting topic because you when you realize that we've been brewing beer for
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thousands of years but pH as a concept and as a measurement was not invented till like 1924 so it's new pH is new it is by
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definition the concentration and activity of hydrogen ions in solution measured as the negative log of the hydroxy Ides hydrogen ions and hydroxide ions being two sides of the same coin
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um but that very scientific definition is not very helpful for us Brewers as Brewers um it's better to think of pH as a measure of chemical equilibrium in a
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solution and when it comes to our W or when it comes to our water our Brewing water it is essentially a measurement of the balance of hardness to alkalinity in the water so you can have a high mineral
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water and a low mineral water uh at the same water PH same balance but those two waters will have vastly different effects on the mash because you know the mash chemistry is another you know whole other uh box
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of frogs and uh it's the chemical the chemical equilibrium of the mash that dictates how well our beer is going to turn out now something many home Brewers are aware of is the impact of temperature on ph chemical equilibrium
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changes with temperature so you know as you increase the temperature of the solution the molecules vibrate faster they dissociate more the actual equilibrium of that solution changes as a function temperature and so the pH is
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different at every different temperature you measure it at as Brewers going back to 1924 and when pH was you know one reason pH was invented was to help us
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quantify uh changes in the mash but it took a long time to titrate and measure and so it was done at room temperature in the lab and that's where our our standard our gold standard for Brewing
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pH at room temperature comes from five and and so when we talk about Mash pH work pH beer pH it's always done at room temperature and this is per you know both the uh European Brewing
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Congress guides and the asbc methods okay so pH changes with temperature but that was never much of a concern for me because I own a pH meter that has automatic temperature compensation or ATC so no matter what temperature I
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measure at my pH meter will compensate to the true pH right well uh unfortunately no ATC is a very handy dandy function that keeps the pH meter calibrated for you so when
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you come into the lab in the morning or into your Brewery and you calibrate your pH meter you stick it in the ph4 solution at room temperature you stick it the ph7 buffer solution at room temperature that pH meter is now calibrated at room temperature for room
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temperature Solutions if you measure a sample that's at a different temperature the electrode in the pH meter that's calibrated room is going to have a different response due to that change in temperature and so a what ATC
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does is it recognizes that difference in temperature from calibration to your new sample and says okay if I'm calibrated at 70 but this work sample is at 95 the P the actual pH of this sample at
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95 degrees is this which was going to be a little bit lower due to the negative log of the scale is going to be a little bit lower at a higher temperature than it is at r
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temperature and that's why when we talk about the PH range at room 52 to 56 we're trying to measure uh at Mash temperature it's about 310 lower because of that CH that change in temperature so
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um 52 to 56 uh measured at Mash temperature would be 4.9 to 5.3 roughly that you're that same range um but again we're supposed to be cooling the sample down the room
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measuring it there and that's where we're looking for 52 to 56 and yeah I've heard many times that a PH range of 5.2 to 5.6 is what we as Brewers should be aiming for during the mash okay this was something that that bugged me for years
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I chased this down looking at various books various documents and pestering various Brewing luminaries and and um it took me a while to realize um that
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barley is an agricultural material and we grow different varieties of barley in different countries of the world different continents different regions spring varieties versus winter
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varieties um and the optimum p for say conversion that is the optimum pH for the activity of this the satification enzymes the
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amales um each amas enzyme we have we know we have Alpha Beta And limit dextranase and actually there's a few more and there are different isomers of each of those enzymes all of them have
07:27
their own pH specific pH Optima if you isolate them and measure them they're all going to be a little bit different and so when we talk about an Optimum Peach we're actually talking about a a compromise or a you you know you know
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what works best for them as a whole and then we have to take another step back and say well that's this group of enzymes but if we talk about the glucanases the pent penines there's
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there there's many other enzyme groups that also contribute to the breakdown of the starches the solubilization of the starches and the availability of those starches to the anal ases um it's it's a
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whole group of things occurring at the same time that gets us to this Optimum conversion and so in other words we given the fact that Barley's an Agricultural Product that its Optima
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variety per regen and per molster is going to vary a little bit um there is no single correct answer that's what I'm coming up to um we so we talk about a range of conversion that seems to work
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well now the pH of beer is not static it changes as we move through the mash and the boil and the fermentation we start out you know um with our water and our grain we dough in we measure our Mash pH init somewhere in this 52 to 56 range
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that Mash proceeds over the hour pH continues to fall as those hydrogen ions get produced and so by the time we enter the boil the pH of the wart is around five and you will often read about
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various Brewers acidifying their work going into the boil or coming down a knockout you know to get it to that kind of level going into the boil during the boil um you have you know evaporation
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occurring you have hot break forming cold break forming you know a lot of chemistry going on in the boil uh so uh as a result the pH drops by up to another 3/10 during the course of the boil depending on you know many
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factors um so we come out of the boil a little bit lower um and going into fermentation now in fermentation the yeast uh take in amino acids from the work and they take in uh other uh
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nutrients such as your lipids and they excrete protons they maintain this um electrochemical balance inside and outside the cell that is what allows them to draw in these nutrients they
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need is the electrochemical difference uh between the inside of the cell and the outside of the cell that's how they can pass these nutrients through the cell wall so they excrete protons as they feed and uh so pH ends up dropping by
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about another half during fermentation and this is how we get from our Mash pH of 5.2 to 5.6 down to our beer pH about 4.0 to 4.6 now in much the same way that we adjust water salt additions to
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emphasize the hoppiness or the moltin of beer we can use mash pH as a lever to depending upon beer style a little lower beer phach tends to focus flavors and so
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um in the case of a of a Munich helis for example a lower beer pH kind of brightens that singular pale malt character it makes that you know that bready character a little bit brighter and allows you to
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differentiate The Malt and hop character in a in a in a pale logger like that also does the same in a pale L you know in a in a bright pale L um a little lower beer pH tends to focus these flavors um when you go to a dark beer
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style such as a porter or stout or Munich dunkl um a little higher pH and again this would be like say 4.3 to 4.6 um would help Open up The Malt
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flavors and so when you're using several specialty malts in the dark beer having that little higher beer pH helps open up those flavors and allows you to taste the different specialty Ms that you've used you get the little hint of caramel little hint of you know roast um it
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makes it that beer more complex whereas if you have a low deer pH in a dark beer those Focus those flavors are a little bit more focused and you would only perhaps perceive kind of a singular
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roast character you know not going to taste bad it is just going to be kind of focused it's not going to be as complex as it potentially could be all right to be completely candid here I don't find myself considering Mash pH on most of my
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brw if Brew father tells me my combination of Brewing water and malt is within range I'll not bother measuring it or making adjustments but but maybe I should be I mean how much difference in the finished beer does this really make
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this level of water adjustment and this level of detail in terms of beer pH and so on you're talking about maybe a 10% difference in the final beers you know in the perception of flavor of the final
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that final beer it is it is very often noticeable and significant but it's a very small difference between the beers um so when I talk about the your five
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Brewing priorities you know for a great beer sanitation you know yeast management yeast temperature control recipe and ingredients water adjustment is like number six on the list pH is is
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definitely significant but it is it's that final tweak to make a good beer great or a good beer mediocre and of course with this being brutos ophy the effective pH adjustments in beer is something we've run multiple tests on I
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presented two such experiments to John but before we get to those a quick word on today's sponsor ABS Homebrew ABS Homebrew is the new name consolidating ABS commercial ABS small parts shop and Atlantic Brew Supply home brew store all under one umbrella ABS Homebrew offer a
14:35
huge supply of beer ingredients and equipment for online order and fast shipping and if you're ever in the Ry North Carolina area you owe it to yourself to stop by the store and check out their selection or participate in one of the many instore events also be sure to subscribe to their excellent fer
14:52
mentality podcast HED by cat Pierce you can find out more at Atlantic Brew supply.com right to the experiments and first up brew club member Matt skill stad tested the impact of high Mash pH in a cream
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ale Matt added his Brewing water to two kettles and in one Kettle treated his water with 85% phosphoric acid Now Matt added his grains and then saw that the treated water had a mash pH of 5.28 which is considered within the
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optimal PH range while his untreated water batch had a mash pH of 6.12 6.1 at Mash temperature would translate to say 5.8 at room maybe maybe 5.9 hard to
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say but um as we talked about earlier you know conversion is actually more effective at higher pH so the conversion of the mash and the
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production of the sugars is going to pop along just fine at at a higher pH the risk is tannin extraction and silicate extraction with the grain husk creil has less grain Husk in it you know
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than say a comparable OG paleo um or border for that matter um so this is you know one you might not expect as much a stringency
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out of this particular recipe and style as you would uh at the same pH for a porter you might expect a little bit more potential for a stringency from a from a forter by the end of brew a mat
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took a gravity reading to see that both batches were at a near identical original gravity reading of 1050 and 1051 and then he racked the two beers to 2 fermenters pitched a packet of us05 yeast and a few weeks later when fermentation was complete he took
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another set of gravity readings and there was a noticeable difference 1.016 in the high mash phb and 1.012 in the standard Mash PHP the lower finishing gravity is telling us that the
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beta was more active um and it had better conversion or better longevity in the lower pH mash than the higher pH Mash Matt also took pH readings and as expected the beer with the higher
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starting pH at Mash time retained a higher pH in the finished beer the high Mash pH beer was also noticeably clearer but could tasters tell a difference well the beer was presented to 20 participants each participant was served
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two samples of the high Mash pH beer and one sample of the standard Mash pH beer in different colored opaque cups then asked to identify the unique sample now a total of 11 tasters would have had to accurately identify the unique sample to reach statistical significance which is exactly how many
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did now when we get a significant result we ask the participants who identified the odd beer out which beer was their preference and three tasters reported preferring the high Mash phb six like the standard Mash phb better and two had no preference despite noticing a
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difference and in his own tests Matt could pick the odd beer out every single time and he said that to him the high Mash pH beer retained a slight harshness and generally tasted just a bit lifeless whereas the standard Mash pH beer was much cleaner and brighter with a more
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citrusy hop flavor and that kind of follows where as I say you know lower peach tends to focus and brighten flavors higher peaches tend to broaden them in a p L High beer pH just comes across as a uh a more bitter
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beer yeah um and but in a in a logger like a creale where you have a lwh hawk character and you're looking for kind of a brighter malt character to give that beer some life the lower pH beer uh
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would be uh perceived as a as a livelier brighter beer now the second experiment tested boil pH former brw losophy contributor Malcolm Fraser brewed two American ipas making no adjustments to pH during the mash and at the conclusion
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of the match rest both batches were at 5.45 pH Matt then added 2.5 millit of 77% phosphoric acid to one of the batches bringing its pH all the way down to
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5.12 Malcolm then proceeded to boil chill and ferment the two beers in separate vessels while both beers had the same OG the high boil pH beer finished at 1.013 while the treated low boil PHP
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attenuated down to 1.08 there was also a noticeable difference in PH in the finished beer but it was a smaller Delta now so 4.50 to 4.39 so were were the triangle test able
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to differentiate these beers well a total of 42 people participated in this experiment each blindly served two samples of the higher boil pH beer and one sample of the lower boil pH beer while 20 taster would have had to accurately identify the low boil pH
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sample as being different in order to reach statistical significance only 15 did suggesting they were unable to reliably distinguish the beers that said Malcolm reported preferring the higher boil pH beer as he perceived the bitterness is being a bit more assertive
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without being overly harsh yeah in a hoppy IPA a little higher boiled pH would in influence the H hop isomerization you get better isomerization at higher boiled PHS than
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you do at low boiled PHS um because the Hops isomerize better at and higher pH um and so in terms of an IPA character that may lend itself to a bit more
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bitterness and uh that would be a factor for perception of flavor difference between the two beers so one experiment came out significant when there was a large Mash pH difference and the other came back nonsignificant when there was
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a smaller boil pH difference but for me seeing the results of these experiments and in talking to John Mash pH is something I'm going to spend a little bit more time focusing on in the future and I'm going to remember that I need to
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take pH measurements at room temperature even when my pH meter has automatic temperature calibration look a massive thank you to John for taking us through this and for sharing his presentation and John also sat down with me and talked about what happens if you
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mash your beers for a duration other than 60 minutes and you can see that video right here