The REAL mash pH?

[mickp]

OK, my mash is errr, mashing right now. I measured at room temp and got 5.3, which I figure is good enough. This is an amber, so there's a hint of darker malts in there, but not much.

Now, this did make me think of a follow on question. This mash is pretty thick (partly I think due to my adding a half pound of rice hulls per Gordon Strong/Tasty's process). It would seem logical that mash thickness would have an effect on pH. Is this, perhaps, why my pH is slightly low?

Secondly, I measured the pH about 10 minutes after starting the mash. Will it be at equilibrium at that time?

[ajdelange]

OK, my mash is errr, mashing right now. I measured at room temp and got 5.3, which I figure is good enough. This is an amber, so there's a hint of darker malts in there, but not much.

Measured with a meter? If it is it is a bit low (but OK). But nominally one thinks of British pale ale malt as having a distilled water pH of about 5.6. Some alkalinity in the water is the norm and might raise it to 5.65 - 5.7. Modest amounts of dark malts might bring it back to about 5.5 - 5.6. If test strips really have a repeatable bias of -0.3 then one might expect a reading of 5.2 - 5.3.

Now, this did make me think of a follow on question. This mash is pretty thick (partly I think due to my adding a half pound of rice hulls per Gordon Strong/Tasty's process). It would seem logical that mash thickness would have an effect on pH. Is this, perhaps, why my pH is slightly low?

Dilution does have an effect on pH but the stuff in the malt resists that change - this is the buffering effect. If the water being added is low in alkalinity then mash thickness will have little effect. If the water is very alkaline thickness will have a greater effect.

Secondly, I measured the pH about 10 minutes after starting the mash. Will it be at equilibrium at that time?

That depends. Sauremalz can take 30 - 30 min to equilibrqte and some change of pH as one steps through the mashing process is normal. I think it's a good idea to take lots of readings. Once you have gone to the trouble to do a calibration it is very little extra effort to take an extra few readings.

[mickp]

Thanks again AJ.
I am indeed using a meter, so maybe I just overacidified a little. I use bottled spring water, for which the analysis is pretty low in everything, so I know the base water is nothing extreme. Oh, btw, this recipe uses regular 2 row, not British pale malt...not sure if that makes any difference at all.
I'm sparging right now. What I'll do next time I brew (maybe next weekend) is to go slower with the additions and the readings and try to sneak up on the targets so I can get it down. For now I'll be happy with my 5.3.

Thanks for the always awesome info!

[Cliff]

I brewed for years and years with the philosophy that If it Ain't Broke, Don't Fix It.
And lo it works just fine.
Recently I've taken to fiddling with the mash pH and you know what I get for a result?
Not much, that's what. I was getting good conversion before and adding a pinch of Ascorbic and salts, adjusting the pH ever so closely seems not to do much for my beer at all.

But then the water out of the hole in my yard is appropriately acidic . If it were way off one way or the other I suppose I'd have to worry about it. In fact I don't even bother with the Hydrometer any more . I haven't taken the things out in a very long time.
The only nod to tech I use any more is the starch test.

Maybe I'm just friggin lucky and have a happy confluence of ingredients such that so long as I don't swap out something drastic I can just make beer with nary a care.

[ajdelange]

It's certainly been said that better is the enemy of good enough and while that philosophy appeals to some it doesn't to others. One of the neat things about home brewing (IMO) is that the philosphies under which people apporach it are so diverse. I remember one fellow, here I think, who was really proud of the fact that his beers were snowflakes - no 2 alike but all really, really good. He never measured or controlled anything. One would have to suspect that his palate was not that well developed but I never drank his beers. Maybe they all were, really, really good!

I've fought the "better is the enemy..." thing all my life - professionally and in my brewing. It's who I am. As such I can point to a handfull of things that made dramatic improvements in my beers. One of them was pH control (others - low mineral water, use of cylindroconicals, proper oxygenation).

Then I know some good (make that really good) brewers who never mesaure anything but have learned to control things just by brewing and tasting. They come to the same conclusions that the insrtumentalists do - it just takes them longer.

Anyway, if a brewer is happy with what he has and is unwilling to risk a bad batch or two against the possible rewards of better beer, so be it. He's enjoying his hobby and that's what counts.

PS: Well water is not "appropriately acidic". As soon as it hits the HLT or mash tun the acid (carbonic) is gone and the pH rises. Even water that measures low pH out of well can be highly alkaline and, when the CO2 flies off, it is this alkalinity that controls the day.

[TimmyR]

AJ - great explanation (as always) of pH. I am finding I am consistently on the high side of mash pH and hesitant to adjust too much. I like to use Palmer's spreadsheet as a baseline and find that my mash pH typically starts around 6.0. My last batch, I added just under 2% acidulated malt and dropped the pH to a reading (Milwaukee ATC corrected pH meter) to 5.8 with a temp reading of 42C on the meter. I did not recalibrate the meter prior to use this time. I'd be happy to post my water analysis and adjustments if that'd be usedfull.

Ingredients:
25.0 lb Pilsner Malt
3.0 lb Munich 10L Malt
1.0 lb Belgian Aromatic
1.0 lb Caramel Munich 80L
0.6 lb Acidulated Malt
8.0 oz Belgian Special B
8.0 oz Chocolate Malt
1.4 lb Belgian Candi Syrup
2.0 lb White Table Sugar (Sucrose) (late boil addition)

Mash In - Liquor: 11.36 gal; Strike: 159.28 °F; Target: 149 °F

This is only my 3rd or 4th batch where I've measured and adjusted pH and although am not sure I can taste the difference, my last 3 batches have been well received, seemed "brighter", and done well in some small competitions. My last batch (IPA) started at 5.86 and after 16 oz (3.4%) acidulated malt it dropped to 5.65. Before that an APA I brewed went from 6.04 to 5.83 after adding 8 oz acidulated malt (1.9%). In all the cases I could not taste and sour flavor in the final product.

Sorry for not really have good controlled analysis and for not digging further in to the forum archives as I am sure you have addressed this a few times.

Do you think the acidulated malt should be capped at some percentage of the total grist? My second question is should the pH meter be re-calibrated each brew session?

[ajdelange]

...my mash pH typically starts around 6.0. My last batch, I added just under 2% acidulated malt and dropped the pH to a reading (Milwaukee ATC corrected pH meter) to 5.8

This is, theoretically, exactly what should happen: 2% of grist, 0.2 drop in pH.

..with a temp reading of 42C on the meter.

This is a high for pH measurement. It should be done at around 21 °C. This is the standard temperature and it is much less stressful on your electrode (it will last longer).

I did not recalibrate the meter prior to use this time.

They need to be calibrated each brew day. I have an electrode that, when it was new, held calibration for weeks but that is unusual (or this manufacturer has some innovative process that results in unsually stable electrodes). But you cannot count on having an electrode like this one.

I'd be happy to post my water analysis and adjustments if that'd be usedfull.

Yes it would because...

My last batch (IPA) started at 5.86 and after 16 oz (3.4%) acidulated malt it dropped to 5.65.

That doesn't follow the rule of thumb. You would expect 5.52.

Before that an APA I brewed went from 6.04 to 5.83 after adding 8 oz acidulated malt (1.9%).

But this one does. You have to expect some variation, of course. A rule of thumb is only a rule of thumb.
Also it would help to see the water analysis because you have specialty malts in there which should have gotten your pH down a bit (and perhaps they did) but it's always best to have the complete picture.

In all the cases I could not taste and sour flavor in the final product.

You won't at the levels you mentioned.

Do you think the acidulated malt should be capped at some percentage of the total grist?

It needs to be capped at the level at which you find it has a detrimental effect on the beer. I'd start to get nervous above 4%

[mickp]

Just sayin' here...
AJ needs "cool forum dude of the year" or something award, 'cause he's the most patient, thorough and enlightening poster around (and there are quite a few). Despite answering small variations on the same questions many times over, there's almost always some new snippet and all very patient and positive.
You're making my brewing more enjoyable and, hopefully, more tasty too, AJ.

You rock. Cheers.