Author Topic: Sparge Water Temperature and pH  (Read 3083 times)

Offline pmallory

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Sparge Water Temperature and pH
« on: August 23, 2011, 12:45:05 AM »
When I sparge, my water in my hot liquor tank drops about 10 degrees over the 30-45 minutes it takes me to sparge. I usually start at 170 and it drops to 160, which is low. I am thinking I could start quite a bit higher. At 178 I'm not so sure I would leach out tannins which would be the main concern with sparging at a high temperature. The reason is because the pH is still relatively low at the beginning of the sparge and only at the end of the sparge would leaching be an issue. But, at the end of my sparge, my water has dropped 10 degrees so a high pH would not be an issue. Having my water go from 178 to 168 doesn't seem to be a problem for this reason.

Me and some other brewers were trying to figure out how decoction mashing worked, as in why it didn't leach tannins out of grain even though you are boiling them. We concluded it must be because the grains in the thick mash that is boiled keeps the pH low and doesn't allow leaching because both high temperature and high pH are required for the leaching of these tannins.

Any thoughts?

Offline tygo

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Re: Sparge Water Temperature and pH
« Reply #1 on: August 23, 2011, 03:36:57 AM »
Sparging with cooler water really isn't a problem, especially not water at 160F.  That should work perfectly fine. 

Also, I believe the problem with tannin extraction is with alkaline water at over 170F.  You can add some acid to the sparge water to drop out the alkalinity.  Or if you're using RO water then you don't have to worry about it at all.
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Offline denny

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Re: Sparge Water Temperature and pH
« Reply #2 on: August 23, 2011, 08:04:24 AM »
In my experience, you are correct.  pH seems to be a far larger issue than water temp for tannin extraction.  I typically use 190F water to sparge without any problems.  Especially if you're batch sparging.  In that case, pH becomes even less of a concern.
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Offline gogreen437

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Re: Sparge Water Temperature and pH
« Reply #3 on: August 23, 2011, 09:20:30 AM »
In my experience, you are correct.  pH seems to be a far larger issue than water temp for tannin extraction.  I typically use 190F water to sparge without any problems.  Especially if you're batch sparging.  In that case, pH becomes even less of a concern.

Just out of curiosity, why the 190F sparge water? 

Offline denny

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Re: Sparge Water Temperature and pH
« Reply #4 on: August 23, 2011, 09:30:21 AM »
In my experience, you are correct.  pH seems to be a far larger issue than water temp for tannin extraction.  I typically use 190F water to sparge without any problems.  Especially if you're batch sparging.  In that case, pH becomes even less of a concern.

Just out of curiosity, why the 190F sparge water? 

To get the grain bed into the mid 160s.
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Offline bluesman

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Re: Sparge Water Temperature and pH
« Reply #5 on: August 23, 2011, 09:45:59 AM »
I believe the problem with tannin extraction is with alkaline water at over 170F.  You can add some acid to the sparge water to drop out the alkalinity.  Or if you're using RO water then you don't have to worry about it at all.

+1

Your "mash temp" is targeted to 168F for sparging so your strike water is usually going to be much higher, typically 190ish depending on volume of grain, temp of grain, etc...

Your mash pH should be maintained less than 6.0 during sparging to reduce the risk of tannin extraction. If it goes above 6.0 then it should be acidified to maintain a ph<6.0.
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Offline thcipriani

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Re: Sparge Water Temperature and pH
« Reply #6 on: August 25, 2011, 09:08:47 PM »
I'll be Devil's advocate on this one - I've noticed a more tannic character in beers where I climb over 180F on my system without sparge water adjustment (I use RO typically and I keep my mash pH between 5.3 and 5.6) - even though, given that I typically use single infusion, my grain bed NEVER climbs over 170F. Even though I'm COMPLETELY NOT supported by any literature I can find - anecdotally, I've noticed a difference when I don't use acid in my sparge and my sparge temp gets over 180F - just offering another opinion.
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Offline Pi

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Re: Sparge Water Temperature and pH
« Reply #7 on: August 26, 2011, 05:24:53 AM »
So, typically I fly sparge, but next brew i want to try batch sparging (dont want to morph into the batch sparge/fly sparge debate here). If I raise mash temp. to 170*F and hold for say 15 minutes, pull my first runnings, then do you check the end of the first runnings pH and adjust the sparge water?
It is my understanding the maintaining a mash pH between 5.3-5.9 is important for bertter efficiency/most fermentable wort, does adjusting the sparge pH have much of an effect on the brew?
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Offline hokerer

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Re: Sparge Water Temperature and pH
« Reply #8 on: August 26, 2011, 06:10:24 AM »
So, typically I fly sparge, but next brew i want to try batch sparging (dont want to morph into the batch sparge/fly sparge debate here). If I raise mash temp. to 170*F and hold for say 15 minutes, pull my first runnings, then do you check the end of the first runnings pH and adjust the sparge water?
It is my understanding the maintaining a mash pH between 5.3-5.9 is important for bertter efficiency/most fermentable wort, does adjusting the sparge pH have much of an effect on the brew?

When you fly sparge, the longer you sparge the more dilute the wort becomes.  It can reach a point where it's so dilute that there's not enough acidity from the grains to keep the pH from getting too high.  With batch sparging, you're not "diluting" things.   Since you're just draining and not adding water as you go, the concentration stays the same as does the pH.

As for the sparge water (second runnings), think of that as being sort of the equivalent point in the process as being halfway through a fly sparge.  There hasn't been enough dilution to mess with the pH by that point.  There should still be plenty of oomph left in the grains to get the pH of the sparge down to where it needs to be.
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Offline hoser

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Re: Sparge Water Temperature and pH
« Reply #9 on: August 26, 2011, 06:29:22 AM »
For the most part with batch sparging, the mash pH/grain bed pH is somewhat set.  It would take a lot to shift it, in my experience.  Or at least I would not worry about it if I pretreat my sparge water with acid.  I generally set my sparge water at a pH of approx. 6 if using tap water.  With R/O water I do not worry about my sparge water pH.  The grain bed is fairly resistant to large temp changes as well with batch sparging.  I generally infuse a gallon or so, depending on the recipe, to get my 1st and 2nd runnings of equal volume.  The water I add back for the second sparge is generally pretty hot.  It is the grain bed temp, not the sparge temp that you want to monitor.  So, if I mash low like at 148F, I may add 195F to 200F sparge water.  If I mash warmer, say 154F, I generally add 185F-190F sparge water.  I mash in a converted cooler and check the grain bed to make sure the temp is in the 168-170F  range.  But, this is my system not yours and I know my systems parameters.  Every brewer and system is different so you have to find out what works best for you.  Definitely, check your grain bed temps and periodically check your 2nd and if needed 3rd running pH to make sure that they don't start creeping up.

Offline denny

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Re: Sparge Water Temperature and pH
« Reply #10 on: August 26, 2011, 10:11:43 AM »
anecdotally, I've noticed a difference when I don't use acid in my sparge and my sparge temp gets over 180F - just offering another opinion.

Is that water temp or grain bed temp?
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Offline bluesman

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Re: Sparge Water Temperature and pH
« Reply #11 on: August 26, 2011, 02:33:17 PM »
It is the grain bed temp, not the sparge temp that you want to monitor.

This is an important point.

The grain bed should reach 168F-170F during the sparge. So after the sacch. rest, one will need to infuse or rinse with water higher than the targeted temp in order to achieve those temps. Typically the strike temp will be 20-30 degrees higher than the target temp depending on the amount of grist, initial temp of grist and volume of water added. There are some decent brewing programs that will calculate this for you. I like Beersmith 2.
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Offline thcipriani

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Re: Sparge Water Temperature and pH
« Reply #12 on: August 26, 2011, 09:01:10 PM »
anecdotally, I've noticed a difference when I don't use acid in my sparge and my sparge temp gets over 180F - just offering another opinion.

Is that water temp or grain bed temp?

Sorry for the ambiguity - that's sparge water temp. My grain bed never gets over 170. My typical process is single infusion, no mash out, so I tend to end up in the mid-to-upper 160's by then end of the sparge.
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Offline gogreen437

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Re: Sparge Water Temperature and pH
« Reply #13 on: August 28, 2011, 12:29:50 PM »
It is the grain bed temp, not the sparge temp that you want to monitor.

This is an important point.

The grain bed should reach 168F-170F during the sparge. So after the sacch. rest, one will need to infuse or rinse with water higher than the targeted temp in order to achieve those temps. Typically the strike temp will be 20-30 degrees higher than the target temp depending on the amount of grist, initial temp of grist and volume of water added. There are some decent brewing programs that will calculate this for you. I like Beersmith 2.

So there is where I am confused.  I just heat my sparge water to 170F and use that.  After recently listening to an episode of Brew Strong on sparging, John Palmer seemed to say that the sparge water (not the grain bed temp) is fine in the 170F to 175F range.  In fact, he even suggested you could just use warm water and it wouldn't make much difference.  When describing the original mash process he said nothing about doing a mash out in regards to the first runnings, and in How to Brew he states that many homebrewers skip this step and it doesn't negatively affect their beers.  All this is a long way of saying that I don't do a mash out and I only heat my sparge water to 170F.

But, after reading a comment from Denny the other day who said he heats his sparge water up to 185F (or something along those lines) I was confused.  So I looked into Denny's batch sparging tutorial.  It makes reference to doing a mash out, but also makes reference to getting the grain bed to 165F to 168F during the sparging process, but doesn't really explain why.  I understand a mash out is to stop enzymatic activity.  But once that has been done, what is the benefit of raising the grain bed temp to 165F to 168F during *edit* sparging?  I'm sorry for the very long winded question, but I want to understand as much as possible.
« Last Edit: August 28, 2011, 12:41:17 PM by gogreen437 »

Offline denny

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Re: Sparge Water Temperature and pH
« Reply #14 on: August 28, 2011, 12:54:47 PM »
But, after reading a comment from Denny the other day who said he heats his sparge water up to 185F (or something along those lines) I was confused.  So I looked into Denny's batch sparging tutorial.  It makes reference to doing a mash out, but also makes reference to getting the grain bed to 165F to 168F during the sparging process, but doesn't really explain why.  I understand a mash out is to stop enzymatic activity.  But once that has been done, what is the benefit of raising the grain bed temp to 165F to 168F during *edit* sparging?  I'm sorry for the very long winded question, but I want to understand as much as possible.

I'll try to clarify things a bit....I used to believe in a mashout for 2 reasons.  One was to stop the enzymatic activity and "fix" the fermentability of the wort.  The other was that it would reduce the viscosity of the wort and improve the runoff.  I've since found that in order to denature enzymes you need to hold 170F for 20 min.  I've never done that, and I suspect not many homebrewers do, either.  In addition, I realized that you're bringing the wort to a boil very quickly with batch sparging, so you don't even really need to worry about denaturing enzymes (the boil obviously does that  To the second point, I realized that even if raising the temp really did reduce viscosity (and I question the extent to which that really happens), you got no benefits from it.  I tried sparging with cooler water and didn't really see any change in efficiency or fermentability.  In reality, even if I added 190F water, the grain bed still rarely reached 170.  These days, I don't worry about a mashout step per se, but sparge with water that's at least 190F.  That in effect gives me a beta/alpha step mash, which I think does increase my efficiency a bit by promoting fuller conversion in the mash.

And while it may or may not matter in this instance, keep in mind that John is almost always speaking of fly sparging, not batch sparging.
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