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Batch vs Fly Sparge - water treatment

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mchrispen:
I want to confirm something.


There should be no difference in liquor treatment for sparging between fly or batch processes, correct? Specifically most people are asking about acidifying the sparge water, and a few citing the time of contact with the grains. Very short for batch, of course, relative to a long fly sparge.


I have been telling them there should be no difference, but with the volume of inquiry - I am wondering if I might be incorrect or there is a source of information that I am unaware. I also tell them that when using RO or DI water for sparge, there should be no need for acidification as the alkalinity is very low. FYI - I titrate my sparge water to 5.8 as insurance against tannin extraction with just a few mL Lactic.


Colby says this - but it is more about the acidification concept than sparge process. http://beerandwinejournal.com/acidify-sparge-water/


Denny?

Jimmy K:
The difference as I understand it is that with fly sparging, as runoff gravity drops the buffering power of the grains decreases. So at the end of runoff, a moderately higher pH/alkalinity sparge water will start to extract tannins as the mash pH rises. But with batch sparging, gravity never gets that low so unless the sparge water is extremely high alkalinity - no problems. (Even if it is high, like my water, still probably no problems.
 
Short answer - good water for fly sparging is good for batch sparging. Good water for batch sparging may or may not be OK for fly sparging.

mabrungard:
The need to treat sparging water has more to do with its initial alkalinity than its mode of sparging. I don't acidify my sparging water because it is RO water with very low alkalinity. However back in Tallahassee, it was pretty important that I acidified my sparging water due to the somewhat high alkalinity of the tap water.

Be careful with assuming that titrating sparging water down to a certain pH will be sufficient for reducing tannin extraction. In Matt's case, I recall that he uses RO and that 5.8 pH target is safe. For someone with really high alkalinity tap water, that 5.8 pH may still leave a LOT of alkalinity in the sparging water and there could be tannin extraction. That is why a pH target is not ideal. A better target is to reduce the sparging water alkalinity to somewhere around 25 ppm (as CaCO3) or less. Depending upon the starting water alkalinity, the ending pH might be much lower than 5.8. However, since we don't need to take the sparging water pH any lower than the mash pH target, a lower pH target of around 5.2 might be the lowest any brewer would need to take their sparging water...regardless of the resulting alkalinity.

denny:

--- Quote from: mchrispen on April 15, 2014, 06:15:57 AM ---I want to confirm something.


There should be no difference in liquor treatment for sparging between fly or batch processes, correct? Specifically most people are asking about acidifying the sparge water, and a few citing the time of contact with the grains. Very short for batch, of course, relative to a long fly sparge.


I have been telling them there should be no difference, but with the volume of inquiry - I am wondering if I might be incorrect or there is a source of information that I am unaware. I also tell them that when using RO or DI water for sparge, there should be no need for acidification as the alkalinity is very low. FYI - I titrate my sparge water to 5.8 as insurance against tannin extraction with just a few mL Lactic.


Colby says this - but it is more about the acidification concept than sparge process. http://beerandwinejournal.com/acidify-sparge-water/


Denny?

--- End quote ---

Acidifying sparge water is probably less important for batch sparging than for fly sparging.  Unless your water has very high alkalinity, acidifying batch sparge water shouldn't generally be necessary.  I can't imagine that contact time has any bearing at all.

mchrispen:
Hmmm... so at a minimum, the focus on pH is incorrect. I should focus more on alkalinity - which makes sense. Thanks Martin.


Denny, can you expound a bit? I am a bit confused - it would seem the same regardless of process, with the exception of higher levels of water/grist at a given time window than fly. I am guessing that having the full volume of sparge water (or half) could provide a greater opportunity for alkalinity to cause a dangerous rise in pH, since the mash pH should have stabilized by this time. The sparge water will almost always be more alkaline than the mash. Or are you saying - using the correct water chemistry and volumes to begin with - most people will not see mash pH rise to "tannin/astringent" levels?


FYI - absolutely not trying to make an argument or case against batch sparging.


I do use RO water, and occasionally skip the acid step. I just checked the TDS and KH of my RO - and it looks like time to change the filters.

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