DIPA using RO water chem question

[Mrboost21]

Do I need to bump down the Acid grains on this? It's 3% of the grain bill
View attachment ImageUploadedByHome Brew1486518943.356161.jpg

 

[Silver_Is_Money]

Do I need to bump down the Acid grains on this? It's 3% of the grain bill

The answer depends solely upon how much alkalinity is present in your water. In my experience, alkalinity dos not correlate well to the waters measured pH, or to TDS, so you will need to analyze it (or have it analyzed).

 

[Dcpcooks]

That's pretty close to the water primer in the brewing science section (which you should read if you haven't yet) . You should be close to 5.2 -5.4 ph. Treat both the mash water and the sparge water equally.

 

[Mrboost21]

I'm using RO which should basically be a blank slate correct?

 

[Silver_Is_Money]

RO water always has some alkalinity that would not be present in DI water. But if it is really good RO it should be close enough for government work.

My homes RO still has loads of alkalinity, because my well water is literally swimming in alkalinity, and the RO unit only removes about 92% of it. What an RO unit ends up with is in great measure a matter of what it is starting out with.

My well has 436 ppm, and my RO has 36 ppm of alkalinity (as CaCO3). DI has (or at least should have) zero.

My guess is that more typical (as in good) RO water has about 8 to 16 ppm of alkalinity. Superior RO water is likely in the range of about 4 ppm alkalinity (as CaCO3).

If you have a TDS meter, and you can get a decent TDS reading of your RO, its alkalinity on first approximation will be half of the TDS reading, This approximation works OK for RO, but don't extend the methods viability beyond RO, or it will likely disappoint you.

 

[Silver_Is_Money]

For a 5.5 gallon (going into the fermenter) batch of typical OG, 1 ml of 88% lactic acid added to the mash water will (on first guess) remove about 31 ppm of alkalinity. 1.25 grams of acid malt will roughly do likewise. The remaining goal is for the rest of the acid malt (or lactic acid) to drop the high pH of the base malts (or more importantly the grist bill as a whole) into the pH 5.4 (ish) range.

 

[Mrboost21]

I use RO from the grocery store. Assuming (until I get a way of measuring) the RO is superior, will my 8oz of German Acid in my grain bill be to much? It's 3% of my grain bill(18lbs DIPA)
And thanks for all of your response. This is brew #24 for me and I'm just now getting into water chem.

 

[Yooper]

I use RO from the grocery store. Assuming (until I get a way of measuring) the RO is superior, will my 8oz of German Acid in my grain bill be to much? It's 3% of my grain bill(18lbs DIPA)
And thanks for all of your response. This is brew #24 for me and I'm just now getting into water chem.

Maybe. When I use RO water, I generally don't need any acid malt in my IPAs, as the gypsum drops the pH enough to bring me where I want to be (about 5.35 usually). Without a pH meter, it'd just be a guess, though.

 

[Mrboost21]

I got the acid malt bagged separately,
I'm going to hit up my homebrew store and see if they have something for me to measure.
Thanks again

 

[mabrungard]

If you are adding a bunch of gypsum, as some do for pale ales, then the acidity that the high calcium dose provides can negate the need for acid malt. For those of us adding gypsum to provide sulfate concentration of greater than about 150 ppm, you probably won't need the acid malt. Boosting the sulfate content even higher could actually mean that a bit of baking soda in the mash might help keep the mashing pH around 5.4 (which is helpful for boosting hopping and bittering perception).

 

[Mrboost21]

Thanks for all the help guys