help with sparge water adjustment

[user 51917]

My water is 9.2 PH and im haveing an astringency problem
Through the help of many HBT'ers I believe that my sparging is drawing tannins out of the grains

My question is should I be adjusting my sparge water all the way down to 5.2-5.4 or a different # and also what to use? Lactic acid?

Thanks

 

[mabrungard]

pH is only a symptom. You really need to be looking at the alkalinity of your water. We typically bring sparge water pH down to the 5.5 to 6.0 range, but what we're really doing is knocking out excess alkalinity. Taking sparge water down to 5.2 to 5.4 is more than necessary and it further risks the development of flavor defects when using flavored acids such as lactic.

Sparge water acidification is a good idea if your water has significant alkalinity. If you sparge with distilled or RO water, the alkalinity may be low enough that acidification is unnecessary. When alkalinity is low, the amount of acid needed to drop the pH is also low.

Bru'n Water includes the water acidification calculations presented by AJ Delange. They have worked very well for me over many years. You do need the water alkalinity information in order to perform the calculation though.

 

[user 51917]

From my ward lab report i have
Ca 3.2
Mg 1.4
Na 39.0
SO4 3.0
Chloride 35.0
Bicarbonate 40.0

I didnt see alcalinity I guess Ill check again
Thanks

 

[mabrungard]

Alkalinity is probably on there somewhere. Bru'n Water shows that a bicarb concentration of 40 ppm will indicate an Alkalinity of about 33 ppm (as CaCO3) if the water pH is somewhere between 7 and 8.

 

[ajdelange]

Ward labs reports do contain alkalinity information. But the bicarb is the same information. It is fortuitous that potable water rarely has a pH higher than 8.3. In such cases the alkalinity is simply 50 times the bicarbonate concentration divided by 61 so that 40 bicarb is equivalent to 32.8 alkalinity. You are one of those rare cases where the pH is outside the range where this approximation works. At pH 9.2 40 ppm bicarbonate corresponds to 40.4 alkalinity. That's not a whole lot of difference relative to the approximation in terms of what we do in brewing. More to the point is that it isn't a lot of alkalinity. You ought to be able to sparge with this water without having the pH go over 6 and get most of the sugar. If you do decide you want to neutralize this it won't take much acid to do it and so it doesn't matter much if you go to 5.5 or 6. IOW this is an application where pH strips should be accurate enough.

Because of the small amount of acid required it shouldn't matter much which acid you use. Homebrew shops all seem to sell lactic but if phosphoric is available it is more flavor neutral.

 

[nilo]

Can anyone share a formula that we enter the water alkalinity, volume and starting PH and it tell us how much lactic 88% or phosphoric acid one needs to add to reach a given final PH?
I know this is part of tools from kai, Palmer and Bru'n, but it would be nice to have the formula, please!

 

[ajdelange]

That's all explained at http://ajdel.wetnewf.org:81/Brewing_articles/Water_acidification.html

 

[Kaiser]

Can anyone share a formula that we enter the water alkalinity, volume and starting PH and it tell us how much lactic 88% or phosphoric acid one needs to add to reach a given final PH?

Not a formula, But I have a table that shows how much acid you need to neutralize 100 ppm as CaCO3 alkalinity:

from Mash pH control

The final pH is less important than the final alkalinity. Once you neutralized the alkalinity the pH will change very easily even with small additions of acid since neutralizing the alkalinity means neutralizing the water's pH buffer capacity.

Kai

 

[nilo]

Looking at the link from AJ, holy cow, now I know why sharing a formula is so complicated.
But I went thru AJ formulas and built this excel calculation tool.
Now, how do I attach this to my signature like your do Kai, with you spreadsheet? In case anyone wants to give it a try.

 

[ayoungrad]

I just read through Briggs' section on water.

My water is pH 8-9 and after having read the section of his book, my plan is to use distilled water with added CaCl2 for sparging. No bicarb added and definitely no tap water. The Ca and absent bicarb will help maintain a low pH and hopefully avoid astringency. This seems to be the overall advice Briggs' book offers and it makes sense with respect to what everyone else has said on this thread.

 

[Kaiser]

Acid calculations can get complicated, especially when you use weak acids where the amount of "active" acid depends on pH. But with the common weak acids that we are using (lactic and phosphoric in particular) the pKas are sufficiently far away from the pH that interests us that I believe it is accurate enough that we can use more simple math.

Nilo, you need to host the spreadsheet somewhere and then you simply add a link to your signature.

Kai

 

[ajdelange]

The complication, IMO, comes from the necessary bookkeeping, not because the math is hairy - there is nothing in the math beyond high school algebra (that is assuming, they still teach them algebra in high school). The fact that Nilo was able to implement the acid calculator in an afternoon attests to this.

 

[nilo]

I don't have a place to host the calculator, so if anyone want the file, PM me and I can email the file.