Water/Grist Ratio's effect on pH

So I was reading up on recipes for a stout I'm looking to brew this weekend.. came across Yooper's Oatmeal Stout. I noticed something towards the end of the 1st post that caught my attention :

From @Yooper :
"Mashed at 156, with a thin mash (1.75 quarts per pound) to keep the pH in range."

I usually mash pretty thin on all my beers as I've noticed I get better efficiency this way, but I never had any idea that this effects pH. It might be covered somewhere in the thread I mentioned above, but I just don't have the time to read through the 60+ pages..

Can anyone explain how water/grist ratios might affect mash pH?

Suppose the water has alkalinity of 2 mEq/L. If you mash with 1 L of water/kg malt the alkalinity of the water is 2 mEq/kg grain. If you mash with 2 L of water/kg, there are, for each kg grain, 4 mEq of alkalinity; twice as much and thus the pH is going to rise.

Thanks AJ... so the thinner the mash, the higher pH you will get?

If the water is alkaline, yes. If it is RO there should be minimal effect but of course in the limit as you add more water the closer the pH of the mash becomes to the pH of the water.

Like temperature? If you add 1L of 100F water to 1L of 50F water, you'll end up with 2L of 75F water (numbers might be off, just trying to paint a picture)

This issue becomes very relevant in no-sparge brewing. A method I use via BIAB.

The work around is not too tricky.

With Bru'n water it is very easy to put in the details of a mash, the grist and the water and get an estimated mash pH. (water report and mineral adjustment done first).

With grain bills containing little in the way of roasted or otherwise darkly colored malts the ph will rise to undesirable levels. (with my tap-water)

Solution add acid. I use acid malt and am finding I need percentages significantly higher than would be used in a thicker mash where a sparge is planned. The most I have used is a tick over 5 %. Usually 1-2% is an oft quoted amount as appropriate in thicker mashes.

The braukaiser has some data on his site where experimental batches with acid malt at over 10% were used without tasters noting anything undesirable.


Example:
My last brew, a Munich helles, 9.25lbs of grain with 5% acid malt and 7.8 gallons of water at dough-in resulted in a measured pH 5.29 ( 45 mins into a step mash and during the sacch. rest). I was targeting a pH of 5.35

Without any acid malt the estimated pH was 5.9 if memory serves.

I would love to use Bru'n Water but I don't have Microsoft office on my computer.. is there any other programs that don't require Office?

hanuswalrus said:

I would love to use Bru'n Water but I don't have Microsoft office on my computer.. is there any other programs that don't require Office?

Click to expand...

You can download OpenOffice..it is free and supports most, if not all, MS Office file types.

Biscuits said:

You can download OpenOffice..it is free and supports most, if not all, MS Office file types.

Click to expand...

Awesome, I'll try that. Thanks man!

So I got Bru'n Water now.. YES! I have a question about that now.. I typically use distilled water for my mash and tap water (Chicago) for the sparge. I'm wondering how I should enter that into the spreadsheet.

hanuswalrus said:

So I got Bru'n Water now.. YES! I have a question about that now.. I typically use distilled water for my mash and tap water (Chicago) for the sparge. I'm wondering how I should enter that into the spreadsheet.

Click to expand...

You should be able to manually set the ratio of RO/Distilled water to tap water in both the mash and sparge water.

It's normally preferred to use RO water for sparging as it's not as likely to raise the pH as most tap water is.

After you mash and drain the first runnings, the pH rises because a lot of the acid from the malt has left. This means that adding alkaline water during sparge can raise the pH above what's recommended.

You could also safely sparge with somewhat cooler water. Warmer water might make the sparge flow easier, but if you keep it below 170 it should still work without risk of tannin extraction. I think Kai has done experiments sparging with 150 and maybe even cooler water.

EZwater calculator is another that many swear by. I have not used it.

http://www.ezwatercalculator.com/

Homercidal said:

You should be able to manually set the ratio of RO/Distilled water to tap water in both the mash and sparge water.

It's normally preferred to use RO water for sparging as it's not as likely to raise the pH as most tap water is.

After you mash and drain the first runnings, the pH rises because a lot of the acid from the malt has left. This means that adding alkaline water during sparge can raise the pH above what's recommended.

You could also safely sparge with somewhat cooler water. Warmer water might make the sparge flow easier, but if you keep it below 170 it should still work without risk of tannin extraction. I think Kai has done experiments sparging with 150 and maybe even cooler water.

Click to expand...

This is great info. Thank you.

You will find recommended ranges for certain minerals in the mash once you begin tinkering with that spreadsheet. I think that using distilled water for the mash will result in unfavorable mineral content, in particular, calcium. On that same page of the spreadsheet, you can enter mineral additions to bring your water into a favorable range, and the cells turn green when the concentrations are favorable.

Thanks guys. Yeah I was playing around with it for a good chunk of the day at work today. Figuring out how this baby works. I think I have a pretty good grasp.. I figured out how to set it as a 50/50 dilution of distilled and tap water so I'm going to cut my sparge and mash water with 50% distilled water. If I do that, add 3.5 grams Gypsum to the mash water, and 2.5 grams Gypsum to the sparge water, along with my 2% Acid malt to the mash... it's showing a projected pH of 5.3. Sound about right?

hanuswalrus said:

So I got Bru'n Water now.. YES! I have a question about that now.. I typically use distilled water for my mash and tap water (Chicago) for the sparge. I'm wondering how I should enter that into the spreadsheet.

Click to expand...

Better- use the tap water for the mash, with adjustments, and 100% distilled water for the sparge.

hanuswalrus said:

Thanks guys. Yeah I was playing around with it for a good chunk of the day at work today. Figuring out how this baby works. I think I have a pretty good grasp.. I figured out how to set it as a 50/50 dilution of distilled and tap water so I'm going to cut my sparge and mash water with 50% distilled water. If I do that, add 3.5 grams Gypsum to the mash water, and 2.5 grams Gypsum to the sparge water, along with my 2% Acid malt to the mash... it's showing a projected pH of 5.3. Sound about right?

Click to expand...

Yes, that's about right, depending on beer style. I normally target 5.4 or so for IPAs, and 5.5-5.6 for stouts. You may have to acidify your sparge water, depending on what your water chemistry is, but bru'nwater has a great calculator for that.