How does acidulated account for high sparge water pH?

[goodolarchie]

I have a pocket pH meter and I've always tried to take several measurements including initial / final runoff. I don't think my mash has ever risen above 5.67 pH during/after sparging because I'm generally aiming for 5.3-5.4 in the mash, but this one got me thinking last night.

There are a few recipes that I enjoy the flavor imparted by acidulated malt (weyermann in this case), which coincide with a fly/batch sparge at the end. I adjust salts for both strike and sparge water. But if your water is sufficiently high pH unadjusted (without adding any lactic/phosphoric acid into the sparge), isn't it entirely possible that your pH could rise to the point of tannin extraction? And wouldn't adjusting the sparge water to roughly match (let's say 5.5) the mash pH be ideal?

Just strikes me as odd because I've never combined both acid malt and an acid addition.

 

[mabrungard]

Absolutely!!! This is the main reason I strongly advocate against the use of acid malt as the only technique in brewing beer. If you don’t neutralize high sparging water alkalinity, there will be an increased chance of tannin extraction.

Appropriate alkalinity neutralization is an important component of good brewing.

 

[RPh_Guy]

+1 everything Martin said

To be clear, it's not water pH that matters (you can't accurately measure the pH anyway), but rather alkalinity needs to be neutralized.

 

[Big Monk]

Absolutely!!! This is the main reason I strongly advocate against the use of acid malt as the only technique in brewing beer. If you don’t neutralize high sparging water alkalinity, there will be an increased chance of tannin extraction.

Appropriate alkalinity neutralization is an important component of good brewing.

Or if you’re like me, you no-sparge and Sauermalz is your main acid source!

 

[mabrungard]

I was just talking with a major brewery in Cleveland and they report an occassional tannin issue and they use sparging water that is untreated. Fortunately, its Lake Erie water and the alkalinity isn't crazy high, but its high enough to sometimes present itself.

 

[Hwk-I-St8]

Absolutely!!! This is the main reason I strongly advocate against the use of acid malt as the only technique in brewing beer. If you don’t neutralize high sparging water alkalinity, there will be an increased chance of tannin extraction.

Appropriate alkalinity neutralization is an important component of good brewing.

Does this apply to batch sparge as well?

 

[Big Monk]

Does this apply to batch sparge as well?

Si, Senor.

You want to neutralize excessive alkalinity in any sparge water. Key word being excessive.

 

[eric19312]

Does this apply to batch sparge as well?

I think it is not much of an issue with batch s

Does this apply to batch sparge as well?

I don't have @RPIScotty 's water experience but seems like sparge water alkalinity is just not much of an issue in batch sparging. Tannin extraction is supposed to happen when pH is too high and gravity in the mash is below 1.010. You never see that low of mash gravity when batch sparging. Probably more like 1.025 in the sparge is more likely for typical grain bill. If your mash was reasonable pH during the main mash it is just not going to be far from that in the batch sparge.

 

[Big Monk]

I think it is not much of an issue with batch s


I don't have @RPIScotty 's water experience but seems like sparge water alkalinity is just not much of an issue in batch sparging. Tannin extraction is supposed to happen when pH is too high and gravity in the mash is below 1.010. You never see that low of mash gravity when batch sparging. Probably more like 1.025 in the sparge is more likely for typical grain bill. If your mash was reasonable pH during the main mash it is just not going to be far from that in the batch sparge.

This is true unless, like I mentioned above, the alkalinity of the sparge water is excessive, in which case people know enough to acidify it or use RO/Distilled to sparge with.

Also, "water experience" is a stretch when applied to me. When it comes to actual experience and "skin in the game", Martin and A.J. have me beat.

 

[Hwk-I-St8]

This is true unless, like I mentioned above, the alkalinity of the sparge water is excessive, in which case people know enough to acidify it or use RO/Distilled to sparge with.

Also, "water experience" is a stretch when applied to me. When it comes to actual experience and "skin in the game", Martin and A.J. have me beat.

I work with RO water and build up the profile I want. I target a specific mash pH, estimate it using Bru'n Water and check it during the mash. I was under the impression that worrying about pH for my subsequent batch sparge was a non-issue. If it's something I need to be thinking about, I'd like to learn more. I don't recall seeing anything in Bru'n water for sparge water pH but I could have easily overlooked it.

 

[doug293cz]

I work with RO water and build up the profile I want. I target a specific mash pH, estimate it using Bru'n Water and check it during the mash. I was under the impression that worrying about pH for my subsequent batch sparge was a non-issue. If it's something I need to be thinking about, I'd like to learn more. I don't recall seeing anything in Bru'n water for sparge water pH but I could have easily overlooked it.

It's not the sparge water pH that is important, but rather the sparge water alkalinity. Alkalinity is a measure of how much acid it takes to decrease the pH of the starting water to a particular value. A high pH water with low alkalinity takes very little acid to "neutralize." A lower pH water with high alkalinity takes more acid to neutralize. The more alkalinity in the sparge water, the more it can raise the pH of the mash, and the lower the SG of the wort in the mash, the less alkalinity it takes to raise the pH to 6 or higher.

RO water has close to 0 alkalinity, so using it for sparging cannot affect the pH of the mash much. Thus you are correct that you don't have to worry about adjusting RO water for sparging.

Brew on

 

[doug293cz]

I think it is not much of an issue with batch s


I don't have @RPIScotty 's water experience but seems like sparge water alkalinity is just not much of an issue in batch sparging. Tannin extraction is supposed to happen when pH is too high and gravity in the mash is below 1.010. You never see that low of mash gravity when batch sparging. Probably more like 1.025 in the sparge is more likely for typical grain bill. If your mash was reasonable pH during the main mash it is just not going to be far from that in the batch sparge.

You are correct that it is unlikely to get SG down to the 1.010 range when doing a single batch sparge. It is possible with multiple batch sparges to get the SG down in the 1.010 range.

However, SG is only one factor. The SG will be roughly correlated with the buffering power of the wort. Higher alkalinity can overcome the effect of higher buffering power tho, so the higher the alkalinity of the sparge water, the higher the SG of the wort can be and still get raised to the dangerous level. Adding acid to the sparge water to bring the pH down to 5.8 or less, will reduce the alkalinity of the sparge water to the point where it won't be an issue. It's getting rid of the alkalinity in the sparge water that is the important part.

If you want to determine if your sparge water may be causing a problem, measure the pH of the last runnings. If it is over 5.8, then you should be looking to acidify your sparge water.

Brew on

 

[eric19312]

If you want to determine if your sparge water may be causing a problem, measure the pH of the last runnings. If it is over 5.8, then you should be looking to acidify your sparge water.

Brew on

last runnings is a fly sparging concept...in normal batch sparging with 1 or 2 sparges the pH of the last runnings should be the same as the pH of the initial runnings of the batch in question.

 

[Silver_Is_Money]

Acidulated malt can't account for sparge related pH excursions. Sparge water must be acidified with some other acid.

Over the years I have transitioned from fly sparging to batch sparging to no-sparge. The latter of these solves the entire problem, and for it acid malt works fine.

 

[doug293cz]

last runnings is a fly sparging concept...in normal batch sparging with 1 or 2 sparges the pH of the last runnings should be the same as the pH of the initial runnings of the batch in question.

No. The last runnings is the last wort you collect, whether fly sparge, or the last batch sparge step. If you do a double batch sparge, you have three separate runnings. Which is your last runnings? When batch sparging with alkaline water, the pH from the current sparge step will be higher than the pH from the previous run-off .

Brew on

 

[eric19312]

OK I get it that you can define final runnings in context of both batch and fly sparge. But I can't imagine a situation where it would make sense to be collecting wort with SG lower than 1.010 when batch sparging. My berliner weisse OG is about 1.030 wit pre boil gravity around 1.025 and I seem to think when I made this batch sparging I gout there more or less with equal parts of about 1.035 (first runnings) and 1.015 (second runnings) collections so pretty far out of the danger zone unless I was working with some truly bad water.

Take the same beer and fly sparge and you have a more challenging situation. It is easy to imagine a situation where you need to stop collecting from the mash and just top up the boil kettle with water in order to get that targeted low pre boil gravity and avoid collecting final runnings well below 1.010. And if you are going to be getting close to such low final runnings best be extra careful about pH of the runnings and make sure the sparge water is not alkaline.

 

[RPh_Guy]

I thought badness (not just tannins, but silicates, etc) was extracted with high alkalinity and high temperature, nothing to do with gravity ?

 

[doug293cz]

I thought badness (not just tannins, but silicates, etc) was extracted with high alkalinity and high temperature, nothing to do with gravity ?

As I stated above, lower SG tends to decrease the buffering power of the wort, which means it is easier for alkaline sparge water to raise the pH too high. Also, I recall seeing somewhere on HBT that @mabrungard has experienced excessive tannin/silicate at SG's around 1.010 even at pH less than 6 (sorry, I don't have the link.)

Brew on

 

[mabrungard]

@mabrungard has experienced excessive tannin/silicate at SG's around 1.010 even at pH less than 6 (sorry, I don't have the link.)

Yes, that is true. I use RO water exclusively and it has very little alkalinity and it does not need to be acidified (it would only take a few drops anyhow). But even with that, the gravity of the final runnings has a significant effect on tannin and silicate extraction. It has to do with the osmotic stress that the nearly pure sparging water places on the grain. This phenomena is well documented in texts like Malting and Brewing Science.

And to confirm what others have mentioned above, sparging water alkalinity most certainly does have an impact in batch sparging too. If your water supply has much alkalinity, the most profound thing that you can do to improve your brewing is likely going to be neutralizing that alkalinity for most brewing...and ALL sparging.