Is post boil pH not as important as mash/sparge pH?

[urg8rb8]

I played around with the water chemistry calculators and I noticed that they recommend a certain amount of salts based on how much water is used to mash and sparge. But I couldn't help to think about post boil volume.

Let's say for example I make the same recipe twice to come up with the same post boil volume. However, if the decide to make the mash/sparge volumes different, the calculators will recommend different amounts of salts to maintain a certain mash/sparge pH. But if I boil both down to the same volume, then one will have more salts than the other. What am I not understanding?

 

[Gnomebrewer]

Firstly, salts aren't generally used for lowering pH (even though some do lower the pH, that's not their primary role). Salts are added for flavour. After the pH impacts of the salts are taken into account, the acid required to lower the pH is calculated.

In the mash, Calcium and Magnesium work to lower the pH by countering Phosphates from the grain (which buffer the pH a bit higher than brewers generally want). This same effect doesn't happen in water so salts don't change sparge water pH. So if salts are used to get an acceptable mash pH, the amounts needed will depend on the amount of mash water.

So again, I reiterate, don't use salts alone for pH adjustment. If acid is used for pH adjustment, you can concentrate on getting salts to the level you want for the beer you are brewing.

 

[RPh_Guy]

I think he's saying that the ion concentrations are different post-boil, and that those concentrations may vary based on how much water was used (or rather, how much water was boiled away).
However, the chemistry changes throughout the entire brewing process, not just during the boil.

We adjust water at the beginning because that's the easiest time to do it, and we need to adjust the water at that time anyway in order to hit the right mash pH and subsequent boil pH.
Calculations would get even more complex if you tried to adjust the final ions based on your starting water because you'd also need to account for losses throughout the process.

Totally on board with you there. Over-thinkers unite!

Hope this makes some sense. It's past my bedtime. Cheers.

 

[urg8rb8]

I think he's saying that the ion concentrations are different post-boil, and that those concentrations may vary based on how much water was used (or rather, how much water was boiled away).
However, the chemistry changes throughout the entire brewing process, not just during the boil.

We adjust water at the beginning because that's the easiest time to do it, and we need to adjust the water at that time anyway in order to hit the right mash pH and subsequent boil pH.
Calculations would get even more complex if you tried to adjust the final ions based on your starting water because you'd also need to account for losses throughout the process.

Totally on board with you there. Over-thinkers unite!

Hope this makes some sense. It's past my bedtime. Cheers.

Well, I'm not saying that boiling specifically changes anything. I'm saying if I mash the exact same recipe twice but use different amounts of water to mash, the calculators are going to tell me to use different amounts of salts (target the same pH). But if I boil both down to exactly the same volume of wort, then the concentrations of ions will be different. This would potentially change beer flavor correct?

 

[RPh_Guy]

This would potentially change beer flavor correct?

I see now.


Mash pH is adjusted with either an acid or base.

If you're using water with alkalinity (tap water or spring water), the total amount of acid needed should be roughly the same regardless of how much water is used in the mash BECAUSE the alkalinity in the sparge water also needs to be adjusted.
Lactic acid should be below tasting threshold, or you should use a lower alkalinity water. Same goes for phosphoric acid, if you use that, which has an even higher tasting threshold.
If instead a base is needed, the amount of sodium bicarbonate used in the mash should remain constant regardless of how much water is used.

If you're taking about lengthening the boil and needing to use more water (using tap water or spring water) to compensate for the additional loss, then yes, more acid is needed (and more salts). Indeed the beer in this case may have slightly higher minerality, but considering that the ratios of all the ions will stay the same, and that the percentage change is pretty small, the difference in taste will be almost certainly insignificant.

On the other hand, if you are using a purified water like distilled or RO, then the acid/base needed to adjust the mash pH will stay exactly the same regardless of how much water is used in the mash or added otherwise.
With purified water, it's trivial to maintain consistent ion levels despite variable mash water amounts.

I don't really understand the reason behind the question, but there you have it.

If you want even longer and more technical information (you've been warned), consider asking this question in the Brew Science subforum.

Cheers!

 

[Horseflesh]

I boil off about 15%/hr, and when I figure out my flavor salts I do take care that the final concentrations in the fermenter are still in the right ballpark. Of course this simple concentration calculation overlooks all kinds of voodoo in the mash and kettle.

 

[Gnomebrewer]

If you use acid for pH adjustment and keep the salts for flavour only (as you should be), the concentration of salts in the mash water is the same as the concentration of salts in the sparge water so the mash to sparge ratio won't affect your final ions. You are correct that different boil off rates will result in a slightly different finished water profile, but, as RPh Guy said, the impact would be minimal.

 

[Silver_Is_Money]

Well, I'm not saying that boiling specifically changes anything. I'm saying if I mash the exact same recipe twice but use different amounts of water to mash, the calculators are going to tell me to use different amounts of salts (target the same pH). But if I boil both down to exactly the same volume of wort, then the concentrations of ions will be different. This would potentially change beer flavor correct?

If you are adding minerals to both the mash and sparge water in order to target certain and equivalent mineral ppm's (Ca, Mg, Cl, and SO4) for both, and as long as alkalinity is left out of the picture and addressed separately, isn't your final beer mineral concentration post boiling going to be the same regardless of how much water you choose to mash in, and how much you choose to sparge with? For this case the added mineral quantities remain constant regardless of how you divide up mash and sparge volumes.

I'm aware of many who intentionally do not mineralize their RO sparge water, but this (uniformity of added mineral mass with respect to final beer volume post boil) is specifically the reason why I do mineralize my sparge water.

All of this presumes of course that, just as Gnomebrewer has stated above, mash pH should not be chased and manipulated via mineral additions. Minerals are for flavor, and acids/bases are for mash pH adjustment. Adjusting pH with minerals alters flavor and mouthfeel and dryness perception.

 

[GPP33]

If you are adding minerals to both the mash and sparge water in order to target certain and equivalent mineral ppm's (Ca, Mg, Cl, and SO4) for both, and as long as alkalinity is left out of the picture and addressed separately, isn't your final beer mineral concentration post boiling going to be the same regardless of how much water you choose to mash in, and how much you choose to sparge with? For this case the added mineral quantities remain constant regardless of how you divide up mash and sparge volumes.

I'm aware of many who intentionally do not mineralize their RO sparge water, but this (uniformity of added mineral mass with respect to final beer volume post boil) is specifically the reason why I do mineralize my sparge water.

All of this presumes of course that, just as Gnomebrewer has stated above, mash pH should not be chased and manipulated via mineral additions. Minerals are for flavor, and acids/bases are for mash pH adjustment. Adjusting pH with minerals alters flavor and mouthfeel and dryness perception.

This is what I was going to say. Adjust minerals to achieve a desired ppm level. For this it doesn't matter how much water is used in the mash, the final ppm level will be the same.

Use acids, bases and sometimes mash thickness to adjust the pH. But don't start playing with those additions until you have your mineral content set because some of the minerals will affect your pH and you don't want to chase your tail.

 

[Silver_Is_Money]

This is what I was going to say. Adjust minerals to achieve a desired ppm level. For this it doesn't matter how much water is used in the mash, the final ppm level will be the same.

Use acids, bases and sometimes mash thickness to adjust the pH.

This only applies if there is alkalinity present. If your current software tells you different, get the latest upgrade.

 

[GPP33]

This only applies if there is alkalinity present. If your current software tells you different, get the latest upgrade.

Do explain. Malts acidify the mash especially dark ones, the amount of water will play a role in how much. 1 pound of malt will affect 1 gallon of water much more than it'll affect 10 gallons of water.

 

[Gnomebrewer]

Do explain. Malts acidify the mash especially dark ones, the amount of water will play a role in how much. 1 pound of malt will affect 1 gallon of water much more than it'll affect 10 gallons of water.

What Silver is saying is that the 1 pound of malt will only affect 1 gallon of water more than 10 gallons of water if there is alkalinity present in the water. In distilled water, the water volume doesn't matter.

You are correct that in general (using tap water with some alkalinity) the volume of mash water matters. If you use RO water, mash thickness only makes a minimal difference, however the salt additions to that RO water can mean that there is a difference with different mash thicknesses. If your brewing water is treated with acid to remove the alkalinity, the volume won't affect your mash pH.

We also need to be mindful that this is the Beginners forum, not Brew Science.

 

[SoCal-Doug]

I'll buck the trends here... Except for a very few specialty recipes, I never treat sparge water. A couple other oddball recipes, I will treat the boil based on the sparge liquor added and based on post-boil levels.

Mash water is RO and treated as needed, sparge is pure RO. At the end of the sparge I check the end running's gravity for 1.005 to 1.010, and test the pH hoping for 5.9 to 6.0. Both of which I normally hit just fine, assuring lautering was [in theory] successful and efficient.

 

[Gnomebrewer]

I'll buck the trends here... Except for a very few specialty recipes, I never treat sparge water.

You're not really bucking the trend. There's no need to treat the sparge water when you use RO, because the alkalinity is so low that it doesn't significantly raise your pH. If you used tap water with high bicarbonate (alkalinity) your end runnings pH would be much higher. This water would need treatment. I never treat my sparge water (using collected rainwater). If I want salts, I add them to the boil.

 

[Silver_Is_Money]

Do explain. Malts acidify the mash especially dark ones, the amount of water will play a role in how much. 1 pound of malt will affect 1 gallon of water much more than it'll affect 10 gallons of water.

But the real question is how much will the fixed level of acidity of 1 Lb. of a truly incredibly dark and acidic malt affect 2 gallons of mash water as opposed to 1 gallon of mash water, which would be a simulation of a real world transition from sparging to going no-sparge?

Remember that pH is a base 10 logarithmic scale. And that a logarithm is an exponent. So the scale is exponential, and not linear. And we must deal with exponents....

Example:

If I take 1 gallon of pH 4.00 mash water (wort) solution (caused by adding 1 Lb. of the most incredibly acidic dark malt, which is in fact somewhat beyond imaginable) and dilute it with fully neutral deionized water until it is 10 gallons, its pH is now 5.00 due to the pH scale being log base 10.

10^-4 = 0.0001, and -log(0.0001) = 4 pH to start, wherein the exponent is 0.0001

Now dilute this wort 10-fold, and the exponent now becomes 0.00001, and therefore:

10^-5 = 0.00001, and -log(0.00001) = 5 pH (after diluting 1 gallon to 10 gallons)

But for the case of merely doubling 1 gallon of mash water to 2 gallons (as in going from sparge to no sparge) the exponent only changes from 0.0001 to 0.00009, so:

-log(0.0001) = 4.0000 pH initially for the case of 1 gallon + 1 lb. malt
-log(0.00009) = 4.0458 pH (for the case of diluting 1 gallon to 2 gallons)
and continuing on from there on up to a ten-fold dilution, we get:
-log(0.00008) = 4.0969 pH (for the case of diluting 1 gallon to 3 gallons)
-log(0.00007) = 4.1549 pH (for the case of diluting 1 gallon to 4 gallons)
-log(0.00006) = 4.2218 pH (for the case of diluting 1 gallon to 5 gallons)
-log(0.00005) = 4.3010 pH (for the case of diluting 1 gallon to 6 gallons)
-log(0.00004) = 4.3979 pH (for the case of diluting 1 gallon to 7 gallons)
-log(0.00003) = 4.5229 pH (for the case of diluting 1 gallon to 8 gallons)
-log(0.00002) = 4.6990 pH (for the case of diluting 1 gallon to 9 gallons)
-log(0.00001) = 5.0000 pH (for the case of diluting 1 gallon to 10 gallons)

Thus if we fully double the mash water the pH change with respect to a fixed quantity of acid for this example (and all others) is trivial, and would be quite hard to detect via pH meter. The change from pH 4.0000 to pH 4.0458 for the case of fully doubling the mash water volume is only 1.145%, and for nearly all practical purposes it can be discarded from consideration.

 

[Silver_Is_Money]

After realizing that fully doubling the mash water only moves the pH upward by 1.145%, imagine how truly undetectable an exponential change on the order of 1/5 of this volume shift would be to a pH meter.

Such as for the example case of initially planning to mash 20 lbs. of malt in 10 gallons of DI water, and then at the last second deciding to mash it in only 8 gallons of DI mash water instead.

 

[Silver_Is_Money]

The above example considers the buffering value of malt to be zero, but clearly it is not, so when malt buffering (wherein buffering is the measure of a substances ability to resist change in pH) is lastly considered, the already trivial pH changes with respect to "real world" mash water volume changes are quite likely going to be even less than for my unbuffered example. The way to find out would be to carry out mashes of 1 lb. of malt in 1 gallon, and then separately in 10 gallons of DI water and then compare the two mash pH's at 30 to 60 minutes into the mash.

 

[Silver_Is_Money]

We also need to be mindful that this is the Beginners forum, not Brew Science.

Oops, considering that, I did get rather carried away.

 

[GPP33]

Oops, considering that, I did get rather carried away.

Yea you did. But it's a great explanation of the affect of malt on DI water. I guess the OP could be using DI water but I doubt most people do. Most people are using either tap water which often has significant alkalinity or RO which has some residual alkalinity. I've successfully adjusted pH exactly once by using mash thickness on a stout that I wanted to raise the pH but didn't want anymore sodium. It wasn't by much but it allowed me to nail my desired pH.

So with that I'll stick to my original statement of:

and sometimes mash thickness

Cheers!

 

[Silver_Is_Money]

Does that permit me to stick with my original answer?

This only applies if there is alkalinity present. If your current software tells you different, get the latest upgrade.

Until merely days ago a very popular mash pH assistant software package radically altered DI mash pH value outcomes simply by manipulating the DI water to grist ratio upward or downward. Be sure to get the latest upgrade if this program happens to be your chosen software.

 

[urg8rb8]

I just did an IPA (~15lbs of grain) and I added the following with RO:

I took the mash and sparge volumes out of BeerSmith and plugged them in Brunwater and just played with the additions until I got the desired mash pH and mash water profile concentrations (as above in the Mashing Water Profile row).

Now after reading this thread, I feel like I'm doing this all completely wrong. What the heck am I doing wrong???? Btw, the IPA I made came out freaking amazing!

 

[GPP33]

Does that permit me to stick with my original answer?



Until merely days ago a very popular mash pH assistant software package radically altered DI mash pH value outcomes simply by manipulating the DI water to grist ratio upward or downward. Be sure to get the latest upgrade if this program happens to be your chosen software.

10-4. I assume I am using the one you are referring to, I don’t use DI water but will upgrade none the less.

 

[Silver_Is_Money]

10-4. I assume I am using the one you are referring to, I don’t use DI water but will upgrade none the less.

Good! If the pH output is incorrect for the case of doubling DI mash water volume, it will also be incorrect for the case of doubling alkaline mash water volume.

 

[Silver_Is_Money]

Now after reading this thread, I feel like I'm doing this all completely wrong. What the heck am I doing wrong???? Btw, the IPA I made came out freaking amazing!

The mash water analyticals look quite appropriate for IPA, the mash pH looks normal, you are also mineralizing your sparge water to the same ppm levels, and most importantly of all the beer tastes great. I can't imagine from that where anything is being done wrong.