BIAB, a pH thought...

Discussion in 'General Brewing Discussions' started by okoncentrerad, Nov 29, 2017.

  1. okoncentrerad

    okoncentrerad Active Member

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    Trying to get my head around this thing with brewing chemistry etc, I'm not saying it's a big deal or not, but it would be great if someone could clarify...

    From a mash pH perspective, doing a full volume BIAB vs BIAB with some kind of sparging, the first approach would result in a higher mash pH than the other (same recipe and other conditions)? If so, would it be insignificant or a somewhat significant difference?

    Is it something one should consider when deciding water/grist ratio when mashing, to find out which ratio suits you best, given your water profile?

    I'm just thinking out loud here, not saying things really matters in the end, obviously a lot of people just brew on and get great result.
     
  2. J A

    J A Well-Known Member

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    Interesting question. I've been doing a hybrid approach with a reciprocating mash and substantial sparge but have been thinking of doing a full-volume recip for single-mash, double batches. I hadn't really thought about extra dilution and the effect on PH.
    We have to be careful of higher temps at sparge leaching tannin because the PH has gone up with the thinning of the mash/wort. It seems possible that the same thing could happen with FV mash. The difference being that with the sparge, first runnings are drained out (either all at once for a batch sparge or progressively with a fly sparge) leaving the sparge much thinner and PH higher whereas, with the FV, the stronger, lower PH wort would be part of the mix. That would mitigate the effect.
     
  3. Beer_Pirate

    Beer_Pirate Active Member

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    Mashing grain tends to lower the pH of the solution, so it depends on if you are treating your water or not. Doing a full volume mash, your grains will have less impact on the pH of the starting water, but if you treat the water with phosphoric or lactic acid you can negate those effects. I just recently went down the rabbit hole of water chemistry and for me (doing 5 gal batches) it takes a very small amount of acid to get my water right doing dunk sparge (full volume mash). All that being said, I haven't noticed much of a difference between my beers mashed with and without the acid addition.
     
  4. Nosybear

    Nosybear Well-Known Member

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    First, I think you're thinking backward on the pH (if I understand the original post correctly). Mash pH is important to conversion, clarity and extraction of tannins. The enzymes work best in a given pH range, the generally accepted target is a pH of 5.4 +/- 0.2 in a sample cooled to room temperature (about 20° C, or 68° F). No matter the mash thickness, this is the range you want your mash pH to be in. There are two ways to reduce mash pH, with calcium and magnesium salts and with acid. Both approaches have positives and negatives. After the mash, there are two reasons to consider pH. First, too high a sparge pH can lead to tannin extraction, as you mentioned, resulting in astringency in the beer. Second, a finished beer with too high a pH tastes flat and lifeless. I've done this experiment with my homebrew club: Brew a balanced pH beer (around 4.2 for a final pH), then dose it with small amounts of acid and base solutions. The effect on flavor is profound. Too low and you have a sour beer, too high and it's flat.

    Water chemistry is indeed a rabbit hole. You can go as deeply into it as you'd like. And it won't fix a bad beer. But it will improve a good one into the great range, done right.
     
  5. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    You hit on something. I found the thicker the mash, the lower the pH.

    If the water used to has a significant hardness, particularly bicarbonates, it would have have greater effect of raising the pH with a thinner mash because of the buffering effects of the water. If you were to use softer water (R/O or blended), the buffering effects would be less and I would assume it would reduce the amount the pH would raise compared to a harder water. If the water is soft and the mash is thicker (1.25:1) the pH drops pretty low depending on the grain bill, 5.0-5.2 @ 80 F. Ideally the mash pH should be 5.4-5.6 @ 80 F.

    If you were to do a full mash with no sparge, I think it would work just fine, but I would use softer water to prevent a high pH.
     
  6. Nosybear

    Nosybear Well-Known Member

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    ^^^^ And the pH rises through the mash-sparge-lauter process, that is, until you boil. Makes sense if you think about pH, a measurement of the concentration of H+ ions in the mash. More water would mean a lower concentration of H+ and vice versa. It gets complicated quickly.
     
  7. okoncentrerad

    okoncentrerad Active Member

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    My original thought was about two "extremes"...full volume BIAB vs BIAB with a certain water/grain ratio and where the "sparging" would only consist of filling the boiler kettle with your water to get to the boil volume. If one would do that with your existing water, no additions and adjustments; same conditions in both cases, would the latter give you better control over mash pH, give you less problems with tannins (since no sparging over the mash bed, just filling the kettle) but to the cost of a higher pH in the boil, due to the water addition in the "no-sparge sparge"? Again, not sure if it matters in any big way...I'm just trying to understand whats going on here

    ...IF adjustment to the water would be done, would any of those two do better, theoretically? Not to speak of any intermediate variations on BIAB...
     
  8. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    Each method would require a different approach, but in the end the pH of the mash needs to be controlled. I guess I don't an advantage of either one over the other.
     
  9. Nosybear

    Nosybear Well-Known Member

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    If I understand, what you're proposing is no different in principle than diluting extract with water. You are proposing to do a mash in a bag, remove the bag, then add water to the desired boil volume without sparging? First off, it has no effect on the mash pH because the mash is already over. Tannins don't come into play because there are no grain husks in the kettle to extract them from. What you're doing is losing efficiency - there will be a lot of sugars left in that grain bag that sparging would remove. That's really the only difference: It will take you more grain to get to the volume and gravity you want. "Better" here is subjective, depending completely on what you want to accomplish. If you want efficiency, you'll have to sparge. A no-sparge process will be easier but will leave a lot of sugar in the grain. Sparging with acidified water doesn't generally extract tannins, neither method improves control over mash pH.
     
  10. okoncentrerad

    okoncentrerad Active Member

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    Well yes, my "proposal" was something like that...really just theoretical scenario. It gets complicated, as a noob, lots of parameters to think about. I guess my mind was thinking about that it would be easier to reach your target water profile (including pH) with less water in the mash. Sparge/no-sparge, I understand that's just question of possible tannin extractions vs less efficency.
    Not sure I'm much wiser hehe but I will keep thinking and perhaps in the end start to grasp things
     
  11. Ozarks Mountain Brew

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  12. J A

    J A Well-Known Member

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    You're on the right track. Grist ratio will have an effect on mash PH and one should be prepared to make adjustments with water additives. As I mentioned in my first post, I actually hadn't given that aspect of the process much thought when considering a full-volume re-circulation, but now I can add that to the list of things to do if I set up to mash that way. ;)
     
  13. Head First

    Head First Well-Known Member

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    It sounds like you have a grasp of whats happening in the mash so just for fun pull up the water calculator on this site and play with it. It is a true calculator that does the math for you. By feeding it numbers I think you will get your answers as to how water volume affects PH . It also helps with acidification of sparge water.
     
  14. okoncentrerad

    okoncentrerad Active Member

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    I thank you all for your patience and helpful comments and suggestions :) much appreciated!
     

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