When is RA too low?

[DPB]

I believe I may be doing something wrong and was hoping someone could point me in the right direction or flat out tell me what I’m doing wrong.

I have been messing around with EZ water for a few weeks now before I brew my next batch. I’ve attempted to brew with my own water in December and both batches turned out horrible (I have very hard water) as a result I am attempting to modify RO water.

What I am noting is that the RA is in the negatives by what appears to be a significant amount…but then again I’m no scientist so I’m not sure if it is or is not. At any rate when I add 1 tsp of gypsum (4 grams?) and 1 tsp of Calcium Chloride the RA is calculated at -137. Should I be concerned? When should I be concerned with the RA numbers being too low? I know this also depends on the type of beer as well, but lets say in this instance a “standard” English Bitter.

When I scale up the additions for 13 gallons of water (I am treating all of my brewing water at once) I am adding 18.9 grams of gypsum and Calcium Chloride each. That sounds like a lot. I hope I am doing my math correctly but would not be shocked if I am not.

 

[jmf143]

If you'll post your water parameters and grain bill someone will help you out. That being said, I don't think RA by itself is something to be concerned with. Take my advice with a grain of salt though (either gypsum or calcium chloride).

 

[mabrungard]

It sounds like the OP is trying to modify a very hard and probably very alkaline water for brewing. I assume that they are using acid or adding even more hardness to reduce the RA value.

In the case of water that is already highly mineralized, that approach may not produce acceptable results. This is especially true for water programs that do not provide adequate guidance on maximum ion levels. For the most part, neither chloride or sulfate should exceed 100 ppm. Sulfate may exceed that level when brewing a hoppy beer, but the chloride should then be well below 100 ppm.

Starting with less mineralized water by diluting with RO is a very good way to go. Getting your brewing water guidance from an other program might be a good idea too.

 

[ajf]

I have fairly soft water, and brew a lot of Special Bitters. I also use EZ water, and it works well for me.
I use ~ 9g water per batch starting out with Ca 17 ppm, Cl 13.6 ppm, and SO4 12.9 ppm.
I treat this water with 11 g CaSO4 and 450 mg CaCl2. This gives me an estimated RA of -311.
In Pale Ales by Terry Foster, he recommends Ca 50 - 100 ppm, SO4 100 - 200 ppm, and Cl 20 ppm for an ordinary bitter. Your additions would give you nearly twice the Ca, and 9 times the Cl concentrations that he recommends.

-a.

 

[DPB]

I am afraid I was not very clear in my original post.

I will be utilizing RO water only.
I will be/anticipate using 9.75 gallons, however, I am prepping/treating 13 gallons with gypsum and calcium chloride.
I am trying to follow the water chemistry primer as best I could for a British beer, which I believe calls for "British beers: Add 1 tsp gypsum as well as 1 tsp calcium chloride".
I am assuming 1tsp equals 4 grams.
The grain bill is 7.5lbs 2-Row, 1lb Crystal Malt 2L
I've noticed when I add the gypsum and calcium chloride into ez water the RA values are at -137.

My concern is that the RA levels are too low? I am not sure if they are or not.

 

[ajdelange]

The Primer actually assumes 1 tsp is about 5 grams but it certainly could be 4 depending on how tightly it is packed into the measuring spoon. The 1 tsp is per 5 gallons treated. Assuming 5 grams calcium chloride and 5 grams gypsum per 5 gallons treated the RA should be about -100. That's a lot of calcium (144 mg/L) and a very hard water (360 ppm as CaCO3) but as there is little offsetting alkalinity the RA will be about - 360/3.5 ~ 100. Even so the expected base malt pH shift will be about - 0.17 pH. IOW if your base malt has a DI water pH of about 5.75 your mash pH would be about 5.58.

But if you scale 5 grams/5 gal to 13 gal you get 13 grams, not 18.9 so there is a problem with your scaling. At 18.9 grams of each you will have 146 mg/L calcium and an RA of -146, 214 mg/L sulfate and 211 mg/L chloride in 13 gal. Your anticipated pH shift would be -0.25 for an estimated pH of 5.5 which is not a problem at all but the high chloride and sulfate might be. Absent sodium it might not taste salty (sodium chloride) salty but it will certainly taste salty (minerally). That's OK if it is what you want.

So at a minimum I'd pull back to 1 gram/gal of each salt (13 grams total) or less. You'd want a little sauermalz if you did that. If the beer isn't hop assertive enough or if you want a mineral taste component you can always adjust the salts in a subsequent batch.

 

[DPB]

Got it. Saw what I was doing wrong. Thanks again AJ! I'll also be adding some acidulated malt as well.

Also, when should I be concern with the RA level?

 

[ajdelange]

There is a chart at http://www.pbase.com/agamid/image/57446374. There is nothing on it outside -100 < RA < 150 so while there is no hard and fast limit on RA I guess anything approaching or outside those limits ought to raise an eyebrow.

 

[jdieter]

If I've followed this correctly the OP is advised to add 13 grams of CaCl & CaSO4 and sauermalz to 13 gallons RO water. It seems to me with RO water the sauemalz could push the pH too low... what am I missing?

 

[ajdelange]

The calcium from the addition of 1 gram of each salt gives a predicted pH drop of 0.17 pH relative to the DI water mash pH which, if the base malt DI pH were 5.75 which is a reasonable guess, but it is a guess, would get him to 5.58. That's OK but having it 0.21 lower at 5.48 would make me more comfortable. Adding 1% sauermalz would probably get OP to close to 5.5. Lots of if's, guesses and probably's in there. Best to measure with a pH meter.

What you may be missing is that malts have appreciable buffering capacity. To move them to lower than their DI mash pH's requires acid - some from darker malts, some from the calcium/phytin reaction and some from additional acid provided by the brewer.

 

[jdieter]

I asked about adding sauermalz because I use RO and haven't needed to add any when brewing bitters or pale ales based on ph readings with a claibrated meter.

 

[ajdelange]

I asked about adding sauermalz because I use RO and haven't needed to add any when brewing bitters or pale ales based on ph readings with a claibrated meter.

The Primer is for people working in the blind. In most cases some acid is required and the Primer is intended to cover most cases but it cannot cover all cases. It is much better to obtain and use a meter. That is the only sure way to deal with all the uncertainties I mentioned in the previous post.

I'd be interested as to what sort of mineral additions you do to the RO, what malts you use and and what kind of pH readings you get. It's data.

 

[jdieter]

Here's the info for my last Pale Ale;
16lbs Rahr2-row
2.0lbs Munich
3.0lbs Victory
1lb 80L Xtal
1lb Cara-pils
1lb Wheat

9 Gal. RO mash water with 4.5g gypsum, .9g salt, 4.5g CaCl2, 4.5 Pickleing Lime
9.5 RO Gal Sparge and added about the same salts to the boil, except no pickleing lime
(I do as you and make my water 90/10 RO/Tap)

read 5.6pH in Mash


I forgot about adding pickleing lime and in retrospect my mash may have been slightly high, oh well so much for a 60+ year old memeory

 

[ajdelange]

read 5.6pH in Mash
I forgot about adding pickleing lime and in retrospect my mash may have been slightly high, oh well so much for a 60+ year old memeory

Well sometimes, as in this case, it works to our advantage. If you had added that much lime your pH probably would have been over 5.7 or even higher.