Looking for homebrewing gift ideas? Check out our previous gift guides here or here!
Also, if you enjoy BrewUnited, please consider doing your Amazon shopping via our affiliate link!
Also, if you enjoy BrewUnited, please consider doing your Amazon shopping via our affiliate link!
Am I correct in understanding that the reason that pH is so important when fly sparging is that the slow movement of water through the mash rinses phosphates to the bottom of the mash and into the BK, thereby removing some of buffering compounds and creating high pH in the upper reaches of the mash? And that the reason this is not an issue in batch sparging is that not so much phosphate leaches out in the fast lauter of first runnings, and when you mix in the sparge water you have created a homogeneous mash?
If this is not correct, please explain.
If this is correct, is rinsing of phosphate an issue in a recirculating mash, such as with a Grainfather or Braumeister system? If not, is that because phosphate is reintroduced into the top of the mash or is there some other mechanism at work? Does it make a difference if you have a mash recirculation loop that recirculates the wort back up through the mash?
Posted 34 days ago.
It's more that phosphates are largely exhausted after a recirculated mash, phosphate and bicarbonate. So if your sparge pH is higher than say 7.5, a continuous sparge can cause the lauter pH to raise dramatically, especially if bicarbonate content is moderated to high. So acidification of sparge liquor to 6.0 or less is insurance. The calcium/phosphate reactions yield both oxalates and some mineral salt precipitation in the mash, even when circulated. A circulated mash is more homogenous than a static mash. Oxalates then gather in the top creamy layer of the mash bed.
Maybe better to consider RO or DI for lauter where no carbonates can buffer any residual acidity of the lauter mash.
Posted 34 days ago.
OK, @mattchrispen. I don't think I understood much of this. Can you ELI5?
I am most interested in:
(1) In a traditional fly sparge, understanding why there is a loss of buffering; and
(2)
For someone who was going to do a recirculated mash, what should they
be doing? By recirculated mash, I mean that wort comes out bottom of the
mash, goes through something to heat it (RIMS, HERMS, or kettle), and
is continuously pumped on top of the mash for recirculation. I am
contemplating a single infusion mash most of the time, but I can imagine
a scenario where sparge water is added to the system after the main
Sacch rest and recirculated to achieve more intensive mashing (and a mash-out).
Posted 34 days ago.
Hrmmm. Let's reset back to the AJ proton theory, easier to make the point.
Ca and Phosphate react in the mash freeing hydronium which lowers the mash pH. Carbonates (mostly bicarbonates) in the strike water resist this lowering of the mash by taking up hydronium, which in turn causes various forms of bicarbonate salts to precipitate (sodium bicarbonate, calcium carbonate) as well as facilitate the formation of oxalylates (I need to read up on this chemical reaction, but I am fairly sure oxylate is part of the chemical reaction). This happens relatively quickly as pH stabilizes and achieves equalibrium. With a coarse mill - this will take longer than, say a very fine mill in a static mash (non-circulated), and the agitation and energy added with circulation will help to continually feed acid and base material into the mash (mostly acid) from the more slowly hydrating endosperm.
So in this system, an imbalance of carbonates and acids in solution at the beginning of the mash, stabilize at some equilibrium, hopefully at a desired mash pH. Lautering, even in batch sparging, upsets the equilibrium and causes the pH to rise or fall, depending on the tilt toward imbalance.
So if you are using moderate to highly alkaline sparge water, you are tipping the equilibrium toward basic - causing the pH to rise. If you acidify your sparge water to mash pH, there should be little effect. If you over acidify, then the pH will fall. Also - temperature and rate of circulation will have an effect as they are adding/removing energy to the equation. At equilibrium, there is either a surfeit of acid (hydronium) or base (carbonate species) that maintains the balance. Remember a mash pH of 5.4 is considered acidic.
So, generally you will acidify the mash in to achieve a reasonable mash pH at grain in to overcome any buffering capacity of the liquor. Then the mash will achieve equilibrium (your mash pH), and anything that occurs will change the stasis of that equilibrium (either adding acid or basic liquor) and cause the pH to shift. If the mash pH is 5.4, then a 5.4 pH sparge liquor will maintain the mash pH equilibrium. If the sparge liquor is 7.5/8.0 pH, then you are adding a base to an acidic solution and the strength of the buffer will dictate the shift upward (and rate of shift). A very slow continuous sparge will also have a slow impact on the mash pH buffer, but if basic, can create a scenario where a part of the mash filter is releasing tannins over a longer period of time. Thermodynamics and pressure regulation will govern how quickly the base/acid threshold is mixed.
True fast batch sparging shifts the bulk of the equilibrium shift into the kettle where the additional energy helps to accelerate the impact of the residual acid.
So - generally, after achieving equilibrium, most mashes will see a rise in mash pH during lauter (batch or continuous) when using average US tap waters, except when using of low/no carbonate bearing liquor (RO, DI). If using acid to manage this shift, then the excess acid will prevent (theoretically) tannin extraction during lauter, but will impact boil pH and hop utilization in the kettle.
Did I make it more confusing?
Posted 34 days ago.
>True fast batch sparging shifts the bulk of the equilibrium shift into the kettle where the additional energy helps to accelerate the impact of the residual acid.
I should add to that. Because the period of batch sparging is so short, the period of exposure of the husks and pericarps is relatively short. Release of polyphenols in an alkaline solution is relatively fixed, so 5 minutes releases significantly fewer polyphenols than say, a 45 minute continuous sparge.
Also - the mash bed striates the pH, temperature and PPM of the wort solution. At the top, the PPM is low, likely hotter and generally a higher pH than the bottom of the mash. As a continuous sparge moves along, the gradient of mixing between the high PPM wort and the low PPM wort moves down through the mash but also gets wider.
Batch sparging avoids this problem simply through the time vector.
Posted 34 days ago.
Edit: NOPE - too confusing. Move along.
Posted 34 days ago.
Edited 34 days ago by mchrispen
Sorry for the delayed response @mchrispen. Thanks for the very, very detailed responses!
Yes,
the initial explanation was helpful, and corrected my misapprehension
that it's not the just slow leaching of phosphates to the bottom of the
mash from sparging that is the sole culprit of mash pH issues when fly
sparging.
I now understand that it's also (1) the leaching of
calcium as well, (2) the failure to effectively adjust sparge water pH,
and (3) loss of phosphate and calcium to the collected wort as the
sparge proceeds.
However, I found the balls analogy to be
confusing at best, and probably detrimental to my understanding. Perhaps
I am not as comfortable around balls as you are. :)
This still
leaves unanswered the real question I have about continuously
recirculated mashes in single-infusion electronically-controlled brewing
systems -- such as eBIAB systems -- the type where wort is collected
from the bottom and directly heated by the element as needed and then
recirculated back to the top of the mash. I think can now express the
question more clearly now:
Given this model, considering that
(a) a top-to-bottom gradient of phosphate and calcium will still exist
in this mash, and (b) to the extent that a reservoir of wort is formed
at the bottom of the system, it will have the highest concentration of
phosphate and calcium in the system, then will the recirculation do
enough to "recharge" the mash with phosphate and calcium so that there
won't be a gradient and phosphate and calcium will exist evenly enough
in the mash to not create pH problems? Or are you better off turning off
or omitting the recirculation feature?
Posted 34 days ago.
hmmm. Ignore that last post then. Two possible answers.
One is, it doesn't matter if you treat the entire mash as a black box system. Malt, water, acid/alkali in, check pH during the mash, and at some point it will plateau naturally. Usually somewhere between 15-30 minutes into the first enzyme rest. if you have added all of your minerals and acids into the strike water, and grained in the entire grist - the math is relatively straightforward. Circulation is efficient at incorporating everything in a short period of time. If you toss dry minerals on the top of the mash, it will take longer to incorporate without a good long mixing.
The second answer is - it depends as you dissect the mash bed and look at the layers of grits, goo and husks, and the mash chemistry that seeks to stabilize pH in an ongoing melange of chemical reactions, heat, and circulating liquid. Unless you have a turbulent area in the mash or big dough balls, then assume all ions/enzymes/etc. are available throughout the mash. if you have an overly hot spot, such as temp striation from highly heated wort at the elements, consider that can impact enzyme stability, so you want it firing in such a way to never exceed your required mash temp, a therometer or probe at or very near the element and outlet from the tun. I like to keep at least an inch or two of liquid above the mash to ensure I am not causing channeling, circulating gently with the flow set to the side creating a slow gentle rotation. As long as this level remains constant - your circulation is constant and well distributed throughout the mash and head space.
All that is to say, worry about how the wort flows through your system at a rate that won't over pump the wort being heated from under your mash/bag, piling the water on top of the mash, leaving the element dry firing or boiling a smaller mass of liquid. Everything else, water chem, etc. will fall in place. Premix any minerals and acid in the strike water before grain in. Play with water/grist ratios to find an adequate flow rate, and use a coarse-ish mill to ensure good flow. I like circulation over a static mash, but I also like to overcomplicate.
When lautering, the mash system goes into an unbalanced state, but along the gravity gradient of wort v water. This gradient grows as the wort diffuses into the water. Sparge water usually introduces new bicarbonates (as well as calcium and magnesium) into the mash pH system, taking up acid. So the over all average mash pH rises. The pH at the top of the mash might be 5.8, where the sweet liquor pH running into the kettle might be 5.2. Once in the kettle, the pH will stabilize again and (hopefully) slowly drop to allow hot break formation.
I have a longer detailed description if you want. I think Uberg33k would have a better scientific explanation of the chemistry. Sorry about the balls. :
Posted 34 days ago.
Edited 34 days ago by mchrispen
You can post all this, but you need me to balance equations for you?
Posted 34 days ago.
No but fairly certain I left something out, overplayed the correlation between systems. And I am not a chemist nor mechanical engineer - so happy to be schooled. :) My marble analogy failed utterly.
- There is the pH system in the mash, driven by water composition and malt composition and any additions to achieve a specific goal.
- There is the thermal system in the mash, as heat energy transfers through the tun, mash bed, and free liquids, as well as energy losses.
- There is the mechanical system, in this case flow dynamics with circulation, mash density, sheer and turbulence effects, and pressure differentials.
Which all have correlation to enzyme activity, stability, and total efficiency at converting starch to sugar which is the ultimate goal of the mash.
Posted 34 days ago.
That is a much more succinct way of putting things.
If I understand the initial setup, you're doing a recirc mash. Then when you start lauter, you're fly sparging. Correct? If that's the case, I wouldn't say "buffers get washed down to the bottom". Its more like a fuse burning down; buffers get used up as the new water comes in and uses up their buffering capacity. It would be more accurate to say that they find a new buffering equilibrium, but let's not get all crazy as balls with it (do you see what I did there?). Once you hit a relatively stable equilibrium with your mash in the systems mchrispen laid out, you want to try and maintain equilibrium. That's why you want to try to acidify your sparge so you don't alter the pH significantly as you dilute the sugar content and buffering capacity. Think of buffering capacity as friction. Lowering or raising the friction of a surface doesn't automatically mean you're going to move faster or slower on that surface. It just means the amount of effort needed to move on that surface changes. If you lower buffering capacity, you can swing your pH faster. If you raise your buffer, it's harder for pH to change.
What's driving this question?
Posted 34 days ago.
Remember that time in school when you asked your math teacher 'when am i going to use this!?!?!'
They should have just said "hey, it'll help you make beer someday"
They should have just said "hey, it'll help you make beer someday"
Posted 34 days ago.
Chino is designing a small batch circulated eBIAB system. Guessing he is building this himself, rather than purchasing an existing design, and trying to visualize what is happening in the circulated mash.
Posted 34 days ago.
If that's the case, just buy something off the shelf. I know people love to build things in the homebrewing community, but there are so many systems out there now at so many different price points that you are just better served to find one that matches up with your expectations and pull the trigger unless you're working with a custom fab shop to do some really fancy and precise metalwork.
I keep trying to design something better/cheaper than what's out there and I find to get "better" you're spending a significant multiple more than systems of equivalent capacity and capability. To get cheaper, you basically have to attach negative value to your time and have plenty of it while still being a decent craftsman.
Posted 34 days ago.
Gary just needs a brother thats a stainless welder that owes him some big favors for having to drive his DUI'd ass around ;)
I still need to think of a project for him to do...
I still need to think of a project for him to do...
Posted 34 days ago.
