Effect of wort boiling on ion concentration

[HardyFool]

Hey all!

I have a simple water building question for those of you that build your own water. So, I've been building water from distilled water and CaCl, CaSO4, and occasionally sodium bicarbonate for a few months now, ever since reading the Water brewing elements book, and I've just now discovered a potential hole in my method. My current strategy is to look up the appropriate numbers for the style I'm making from the Water book, plug them into Bru'n water to find the 'per gallon' rate, and then dosing my water at mash and sparge (split proportionally w/r/t respective volumes) in order to get my pre boil wort into the appropriate concentration range. So here's my question: while there are places in the brewing process where water is absorbed or loss wholesale, and thus I'd expect ions to be lost with it (grain absorption, trub), I was wondering if I should take into account the concentrating effect that boiling has on the ion concentrations, especially as my boil off rate is a staggering 25% or so (I brew one gallon batches, and yes, I promise I'll move up to five the second I have my own place).

If that wasn't clear (understandably so), here's an example of a brew day w/ numbers:

let's say I'm brewing a beer that requires PO4 at 150 ppm. A typical pre boil volume for me might be 1.3 gallons. My post boil volume might be 1 gallon flat. Thus, let's say I dose my mash and sparge water exactly right, and my pre boil water is at 150 ppm. Wouldn't my post boil water contain nearly 200 ppm PO4, ignoring removal or addition by chemical reactions I'm considering null (such as the contribution from the mash/a potential acid rest, and the argument can be made of Cl anyway, of course)?

 

[raysmithtx]

I know this flies in the face of what most people do but I adjust my mash pH using phosphorous acid based on my total mash volume. I don't add any water additions to the mash. Once the mash is done I add my water additions using Brun water and I use the final amount into the fermenter to calculate the addition amounts.

I do this for the same reasons you mention.

 

[HardyFool]

I've never though of that, and that's certainly a very simple solution to my problem that I'll likely end up doing. The only potential issue I see from that method is the resulting lack of calcium in my distilled water-based mash, which evidently hinders enzyme activity and stability. I suspect the answer is complicated: I think you would dose the mash up to spec, calculate your "water ion efficiency" as [(pre boil volume)/(mash+sparge volume)], and then add the remaining salts. So, if my mash volume is 1 gal, my sparge volume is .7 gal, my pre boil volume is 1.3 gal, and my fermenting volume is 1 gal, I'd dose the mash to spec, I'd have a yield of 76% (=1.3/1.7), and so I'd add the other 24% direct to the kettle (as opposed to the sparge water to avoid losses due to dead space and whatever else). Then again, given I'm dealing with tolerances around .05 g, I'd probably fare better to just add everything into the boil/fermenter

 

[RM-MN]

You need the ion concentration for the enzymatic reactions in the mash. The mash is over before you start the boil so at that point the changes in the ion concentration isn't as critical. You should notice the flavor changes if your ion concentration is way off but otherwise is of no real consequence.

 

[raysmithtx]

I'm not at my desktop to find it but there's an article in Zymurgy or BYO about the inherent amount of calcium in grains. I believe the article was written by the developer of Brun water. I'll try to post the link later. The way I read it there's plenty of calcium in the grains for good mash conversion (pH is the most important factor) but if the beer needs a lot of calcium for its style you can add it to the boil.

 

[HardyFool]

Raysmithtx,

if that's true, my life would be way easier and I would just acidify my mash, which would for sure lead to more consistent hitting of ion targets, and probably of mash pH. I seem to remember reading something like that, and I always brew all grain (with gravity adjustments only in the boil), so if that's true, case closed. I'll post again if I come across a corroborating article/post/chapter

RM-MN,

I'm sure you're right about the not-hugeness of the change, especially for things like calcium and the minute amount of sodium I add by way of NaHCO3, and I guess concentrating by boiling would preserve the sulfite/chloride ratio, so as long as I hit the middle of the range for each ion, I should have no problems. Then, perhaps, shooting for mid-range concentrations may be the answer in and of itself

 

[raysmithtx]

OK I found the article I was referring to. It's in the Mar/Apr 2015 Zymurgy magazine written by Martin Brungard.

It's a fairly lengthy article but in the "Conclusions" section at the end of the article it states "Calcium is required in brewing water only to the degree needed to enhance desirable flavor, produce adequate beer clarification, and limit beerstone production."

That is why I don't worry about the calcium in my mash water and add it later to get to the levels required for the flavor of that particular style.