Mash pH reading

[Manzier]

Hi all,

I was wondering when the correct time is to take a mash pH measurement? I want to check this ongoing to make sure my salt additions are in the ballpark.

I first through it could be as soon as I've added the grain but I'm assuming there must be some time delay before the salts react with the malt to make phosphorus acid or whatever it is.

-Manz

 

[narl79]

I take one 10 min into my mash.

Sent from my SPH-L710 using Home Brew mobile app

 

[mblanks2]

I usually check mine at :15, :30, and :45 during an hour long mash. Then I check at the end of my sparge.

 

[RM-MN]

The pH of the mash won't stabilize for a few minutes, I've heard that it may take 5 minutes or more but the conversion starts immediately. I've done some experimenting with the iodine test for starch and with the grain milled fine I had full conversion in under 2 minutes. How are you going to get the right pH for the mash if it takes 5 minutes to stabilize and the conversion is done before that?

 

[brewinginCO]

I check the mash 15 min and when I start the lauder. I also measure the last runnings and pre-boil pH.

Also be sure you cool the sample down to room temperature.

 

[wilconrad]

I check it at 5 mins in. The first time I ever checked mash pH, I checked it right after dough-in and it was much lower than I expected (< 5), so I added some slaked lime, then checked it a few moments later and it was all the way up over 6, so I added some acid... you can see where this is going. Give it a few minutes to stabilize (5 mins seems to work for me), then take a reading and adjust if needed.

By the way, I use EZ water to calculate salt additions and I rarely have to do any adjusting after the fact. EZ water is usually right on.

 

[RM-MN]

I check it at 5 mins in. The first time I ever checked mash pH, I checked it right after dough-in and it was much lower than I expected (< 5), so I added some slaked lime, then checked it a few moments later and it was all the way up over 6, so I added some acid... you can see where this is going. Give it a few minutes to stabilize (5 mins seems to work for me), then take a reading and adjust if needed.

By the way, I use EZ water to calculate salt additions and I rarely have to do any adjusting after the fact. EZ water is usually right on.

This is probably the right approach. I did a few pH samples and discovered that my water would make the mash pH too high so I started adding acid blend with the grains. Lately I just add the acid blend as the water is heating but I haven't checked the pH since I started that. I suppose this next batch I should.

 

[helibrewer]

Working my way through Palmer's Water book and it appears about 30 min into the mash is about the right time. The water software out there works really well for predicting mash pH. I use Bru' n water and it has been spot on for me. I use RO water, build my own profiles and with lighter grains always use a little acidulated malt.

 

[mblanks2]

I use Bru' n water and it has been spot on for me.

^This^

 

[bigdongsr94]

RM-NM; full conversion in two minutes? I know I should pm you but I would like to hear more in this.

 

[hophop]

Has anyone checked ph at 1-2 minutes then rechecked at 15-30 minutes? It doesn't make sense to check it at 15-30 minutes when most conversion is finished by then. I set mine after dough in and thorough stir. Sounds like an experiment coming up on my next brew day, but that won't be for a month or so.

 

[RM-MN]

RM-NM; full conversion in two minutes? I know I should pm you but I would like to hear more in this.

I have my grain milled very fine, like coarse cornmeal which works fine with BIAB. I believe my mash temp was 152 for that batch and I stirred the grains in well. I took a sample immediately after stirring in the grains and tested for starch with a drop of wort and a drop of iodine and of course it turned dark blue. I took the second sample at 2 minutes and tested again with the iodine and there was no change in color. I let the mash continue for a total of 30 minutes and then pulled the bag out and started heating the wort.

When I was ready to bottle I checked the gravity and found that it had gone far below the 1.014 I was expecting and seemed to stop at 1.004. The beer doesn't seem to have starch haze and it shouldn't have finished that low if only the alpha amylase had had time to work. I've read that beta amylase takes longer to act but I haven't seen where the time is listed.

 

[bigdongsr94]

Interesting. I really need to crush finer as mine is stock but I'm BIAB. I think it's actually the alpha that takes longer to convert. If I remember correctly I thought of beta as big bites, quick but it miss a lot that ends up raising the FG. Ultra dry beers takes longer to convert. In other words your mash really kicked a$$ as it was pretty low temp mash and converted quick.

 

[brewinginCO]

Has anyone checked ph at 1-2 minutes then rechecked at 15-30 minutes? It doesn't make sense to check it at 15-30 minutes when most conversion is finished by then. I set mine after dough in and thorough stir. Sounds like an experiment coming up on my next brew day, but that won't be for a month or so.

I've checked it at 5min and 15min, and there has been a change in that time.

I always either do an acid rest or a protein rest so I can make sure the pH is correct before I raise to the saccharification rest.

 

[hophop]

I did my experiment today. pH after dough in (1 minute) was 5.1. I rechecked at 20, 40, 60 and ALL were 5.0 to 5.1. Debate can now be settled, as it does not change. And I still stand by my theory of why would you check and set it halfway through a mash after most of your conversion in complete?

 

[wilconrad]

And I still stand by my theory of why would you check and set it halfway through a mash after most of your conversion in complete?

Because if the pH is off by enough, conversion isn't happening as the enzymes aren't functioning

 

[BackAlley]

And I still stand by my theory of why would you check and set it halfway through a mash after most of your conversion in complete?

So that I'll know better the next time.

 

[VladOfTrub]

Some brewing methods use a rest to stabilize pH before going to conversion temps. It is not advisable to start mashing above pH 6 or below 4.7. Different malt types will stick at a certain pH if Phytase hasn't been inverted during the kilning process. If the malt does contain Phytase, it becomes denatured at the higher temps used for conversion. Distilled water is used to determine pH of various malt. To say that pH remains the same throughout the process isn't necessarily, true. It depends on the kilning process of the malt and brewing water profile. Beta and alpha have optimum pH ranges where they do their best, so does yeast. Outside of their pH range they become sluggish, resulting in conversion taking a long time. Ale yeast requires a different pH than Lager yeast. If conversion doesn't take place in 20-30 minutes the mash is too thick or pH is out of whack. Enzymes start to denature with time and temperature. Beta denatures under an hour at 149F. Alpha takes less than two hours at the same temp. Making over night mashing mostly useless, except for saturating grain. Mash thickness plays a part in conversion and with attenuation. A pH of 5 may be hunky dory to a brewer but maybe not to other things taking place during mashing phase. Conversion can begin at 130F, even though the mash isn't at the temp for gelatinizing starch. Beta is active breaking up dextrin at low temps. In certain types of malt, Maltase and Dextrinase are not completely kilned off. They are debranching enzymes that make beta and alpha work better. Alpha, basically liquifies starch and breaks up amylose and amylopectin, forming carbs. It releases certain sugars, and a thing called a-limit dextrins. Beta only works on the non reducing end of the stewed up starch chain, creating sugar and b-limit dextrines. Alpha chops up the chain at certain points, creating more non reducing ends. Debranching enzymes create more non reducing ends. The more non reducing ends, the faster beta works.