Mash ph and off flavours?

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DanMalleck

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I have recently begun brewing after a bit of a hiaitus (new house seemed to have bad brewing juju). I have also been updating my brewing tech with a ph meter and am paying more attention to the mash character. But I have a problem.

I did a traditional English Pale Ale a few weeks back, first with my new meter. Mash ph was 5.6 so I thought I’d reduce it a bit (previous batch had high ph and terrible efficiency so I wanted to get it to about 5.2). I was doing a 3 gal batch and in my tun I had about 7 lb of grain and 10 quarts of water.

Beersmith mash tool told me to add 2.6ml of lactic acid. I added 2.5 (1/4 tsp) and it dropped the ph to 4.7!!! I then adjusted with chalk until I got it to about 5.2. What a mess.

I bottled yesterday and it smelled wonderful, and I was sooo excited to have the brewing curse lifted. I collected a pint from the carboy as I began filling the bottling bucket, and decanted in the fridge. Took a hefty swig and it was… terrible. It had off flavours I’d never tasted, and I was at a loss. It’s hard to describe, but it was an acrid finish that ruined the whole experience. (I know this was pulled from the carboy but still I’ve never tasted something so bad).

I had no idea what happened but then remembered the lactic acid. Could 2.5ml in 3 Gal have caused a radical acrid flavour? (Forgive the mixing of imperial and metric please!)

There are two other things that could have happened. First, I was reusing washed yeast. I was meticulous in sanitation and sterilization, but you never know. Still it didn’t taste like a yeast issue. The only other thing I could think of is some kind of radical infection, but so far I have not had any other indications of an infection—the fermentation finished within parameters and really it didn’t taste like an infection.

Any suggestions? (Also what’s with that mash ph tool being so off?)
 

Sam_92

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I bought a ph meter after a long hiatus as well and what I found is that my mash hits that sweet spot after about fifteen minutes so I've never tried adjusting with acid or chalk.

I'd let this one condition and maybe those flavors will mellow out or disappear.
 

hout17

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I would avoid chalk and add baking soda instead if you need to raise pH. Chalk doesn't dissolve properly.

What was the concentration of your lactic acid as that makes a huge difference? What concentration were you referring to in Beersmith verse what you had in hand?

What model did you use in Beersmith? I find the BW model is very accurate and comparable with Bruin Water.

Also did you calibrate your pH meter on brew day before using it?

Good luck and I hope you get this ironed out.
 
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DanMalleck

DanMalleck

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Thanks for the fast responses. I’ll give quick replies.
Chalk v baking soda. Ok. Noted. Unfortunately BeerSmith doesn’t have a tool to estimate ph increase with alkalines, only acid additions so I was making this up as I went along.
Lactic acid 88%. Same as what BS used in its estimates.
Beersmith 2. I think it’s up to date
Yes meter is calibrated. And then calibrated again when the reading was so wonky.
My main question remains: would that little amount of lactic acid affect the flavour of the beer significantly?
Cheers!
 

hout17

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Thanks for the fast responses. I’ll give quick replies.
Chalk v baking soda. Ok. Noted. Unfortunately BeerSmith doesn’t have a tool to estimate ph increase with alkalines, only acid additions so I was making this up as I went along.
Lactic acid 88%. Same as what BS used in its estimates.
Beersmith 2. I think it’s up to date
Yes meter is calibrated. And then calibrated again when the reading was so wonky.
My main question remains: would that little amount of lactic acid affect the flavour of the beer significantly?
Cheers!

Regarding your mash adjustment using baking soda I was referring to that in regards to building a profile and needing to increase pH which can we done in the water tab and then that adjustment is reflected in the mash tab in BS3 before brewing.

On the fly adjustments are a different story. If I missed my pH I would adjust again next brew (I haven't thankfully yet).

I would say that much acid wouldn't affect flavor from the standpoint of tasting the lactic acid.

@mabrungard will have a better answer on the flavor.

I personally would be worried about my beer not tasting good after having pH go that low and then putting chalk in to attempt to correct though.
 
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DanMalleck

DanMalleck

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Thanks. Those are all good points. I will see how things go and then if this one is still bad once it’s conditioned I’ll redo with appropriate adjustments. I’ve contacted Brad Smith with my question about the mash ph adjustment.
 

RM-MN

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The bad thing about pH meters and brewing is that we feel that since we have them we need to use them. Then we try to adjust our mash pH to what the meter shows it should be.....but mash pH changes during the mash and finally stabilized at about 15 minutes into the mash period. At that point a large percentage of the conversion is already done so we had adjusted too late.

In future brews, take the mash pH at 15 minutes in but don't make any adjustments, just make notes on what it was at 15 minutes. Next time you brew that recipe (exact recipe or it doesn't count) make the adjustments before you mix the water and grain. Check the pH at 15 minutes in and see if you needed to make other adjustments for the next time you brew that recipe. You will need to do this procedure for every recipe as the mix of grains will change the pH of the mash, some will need more acid, some less. Otherwise, forget the mash pH and just brew.
 
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DanMalleck

DanMalleck

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Thanks. I appreciate what you’re saying. Funny thing about “forget the mash ph and brew” is that is what I have been doing and it seemed to my detriment—poor efficiency and I think compromised flavours. I’ve been finding that even though I’m using RO water (which I would mineralize after mashing because again that’s what I thought I should do) my dark beers always taste better than light ones—and of course dark grains are more acidic. I know ph is only one component, but I figured it was time to examine this more closely. Hence the ph meter (ph strips always seemed to be off). I always thought you adjust the ph on the fly but I guess these days with software like BeerSmith it is more practical to plan and then tweak. (Of course, this requires making a lot of beer… :)
 

marc1

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The bad thing about pH meters and brewing is that we feel that since we have them we need to use them. Then we try to adjust our mash pH to what the meter shows it should be.....but mash pH changes during the mash and finally stabilized at about 15 minutes into the mash period. At that point a large percentage of the conversion is already done so we had adjusted too late.

In future brews, take the mash pH at 15 minutes in but don't make any adjustments, just make notes on what it was at 15 minutes. Next time you brew that recipe (exact recipe or it doesn't count) make the adjustments before you mix the water and grain. Check the pH at 15 minutes in and see if you needed to make other adjustments for the next time you brew that recipe. You will need to do this procedure for every recipe as the mix of grains will change the pH of the mash, some will need more acid, some less. Otherwise, forget the mash pH and just brew.

When I did a time course, mine slowly changed out to 30 or 45 minutes. I just take a (cooled) reading at the end now to see how it matched up to software predictions.
 
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hout17

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When I did a tome course, mine slowly changed out to 30 or 45 minutes. I just take a (cooled) reading at the end now to see how it matched up to software predictions.
According to John Palmer 'How To Brew 4e' mash pH will continue to drop very slowly throughout the mash and that the optimal time to check is around 5 - 10 minutes in to the mash I usually do it around 10+ minutes in. He states that we should expect pH to decrease very slowly over the hour long mashing process and to understand that conversion happens pretty quick.

My mash pH readings are usually pretty spot on when taking them at this interval. I use Beersmith 3 and Bruin Water.

Edit: I had a buddy over a couple brews ago that's still getting the hang of it so I made a point to show him my water profile and what I was targeting and broke out my pH meter. I was aiming for 5.4 for a particular stout I was brewing and when we took the pH reading it read 5.4 (at room temp) and he about crapped himself lol.
 
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RM-MN

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Funny thing about “forget the mash ph and brew” is that is what I have been doing and it seemed to my detriment—poor efficiency and I think compromised flavours.

Mash pH and compromised flavours are related. Mash pH and poor efficiency are not very. You need the pH to be way off to get poor efficiency. Efficiency is mostly related to the quality of the crush. If you have never experienced a stuck mash or stuck sparge, your crush is probably not fine enough.
 

bwible

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my dark beers always taste better than light ones—and of course dark grains are more acidic.
I can say you are right as far as efficency goes. I started using acid malt awhile ago for adjusting mash ph. For a 3 gallon batch it usually only takes an ounce or two and a pound lasts several batches. My efficiency went from about 74% to about 81% just doing that. I was always afraid of handling something that says 88% acid.

Dark beers are not only a little more acidic due to the lower ph of the dark malts, but also they often taste better when there is more chloride in your water than sulfate. When you say “light” beers that haven’t tasted good, were they light colored hoppy beers or light colored malty beers?

Do you have a water report for the water you are using? If you are starting with RO and adding minerals, what are you adding and do you know what your approx numbers are for chloride and sulfate?

Dark beers and malty beers will taste better with more chloride than sulfate, or at least with those in balance. Hoppy beers will taste better with more sulfate than chloride. Having way more of one than the other will put the taste off.

It’s just one more thing to look at. I moved in 2019 and I could make good malty beers at the new place but not good hoppy beers. Like you are saying, just a terrible flavor. After several awful brews I got the water tested and found my chloride is almost 8 times higher than sulfate. So this makes sense and now I have to add gypsum all the time,
 

CascadesBrewer

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I appreciate what you’re saying. Funny thing about “forget the mash ph and brew” is that is what I have been doing and it seemed to my detriment—poor efficiency and I think compromised flavours.

Note that the advice was not to ignore mash pH. Instead it was to use software to help predict mash pH, make the calculated adjustments pre-mash (with acid or bicarbonate), measure at 15 minutes (I measure at 30 minutes), and then use the information from your measurement to help guide future brews. If you brewed a batch with 3 ml of acid, and measure high or low, then tweak the amount for the next batch. There are a number of pH models out there. They are all just models and might not actually match the grains that you are using, or your process.

Note that BeerSmith 3 has an update pH model and you can also select between two different models.

Mash pH readings also require an accurate pH meter along with proper calibration, storage and measurement process. I have a $40 pH meter that seems to work okay, but only if I run through a calibration process on each brew day. Also, if you are starting with tap water as your base, there will likely be changes in the makeup from month to month (or more often for some sources).
 

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Beersmith mash tool told me to add 2.6ml of lactic acid. I added 2.5 (1/4 tsp) and it dropped the ph to 4.7!!! I then adjusted with chalk until I got it to about 5.2. What a mess.


Any suggestions? (Also what’s with that mash ph tool being so off?)

i see no one has addressed the ”why was the mash ph tool so off” portion so thought I would chime in (and if someone did and I missed it, I apologize). you say you added 2.5ml (1/4 tsp) of lactic acid. Which did you add, 2.5ml or 1/4 tsp? 2.5ml is 1/2 tsp, so if you in fact added a 1/4 tsp you only added half the lactic acid which makes your huge ph drop even more unusual! When you mentioned your water was at 5.6 to start was that a measured value or something that was from the brewing software? If it was from the brewing software, it could be that your staring water was actually at a much lower ph value than the default provided in the software, meaning you were really lower than 5.6 when you started. Also, I see that you had water reserved for the sparge (as you were doing a 3 gallon batch but only had 2.5 gallon in the mash), is it possible the software had the 2.6ml be the amount to add to your total volume of water as opposed to just what what was used in the mash? This would also be a possible explanation for why the ending value was much lower than calculated after the addition was made.

cheers
 

dmtaylor

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Just popping my head in quick to say that I and some others have started to mash at 5.5 to 5.6, so if I were you, I would not have added anything at all, and thus would have avoided all this mess. Read more here if you have a few hours to waste.



Peace out.
 
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