RO Sparge?

[Wynne-R]

A while back I diluted my carbon block filtered tap water with two gallons of RO. I didn’t notice any change so I forgot about it. Lately I’ve been using three gallons of RO sparge in to four gallons of mash and it’s remarkable. The beer is softer and much less astringent. It’s a pale ale with ten pounds of grain in about 4 ½ gallons. ColorpHast indicates 5.1 in to the brew kettle.

I kinda get the conventional wisdom is to treat all the liquor the same, but my informal results fly in the face of that. An old boss used to say I don’t understand all I know about this. Can somebody tell me what I'm doing?

These numbers are the middle of the range I get from the water company.

pH 8.3
Bicarbonate 111
Calcium 115
Chloride 25
Magnesium 6
Sodium 18
Sulfate 30
Total Alkalinity as CaCo3 112
Total Hardness as CaCo3 127
TDS 225

 

[mabrungard]

There doesn't seem to be that much wrong with that water excepting the alkalinity. It should be fine for darker beers, but might produce a higher than desirable mash and kettle pH with lighter beers. The dilution helped cut the alkalinity and probably helped drop the pH somewhat. You might want to target about 5.0 in the kettle if using colorphast strips.

By the way, the calcium and magnesium appear to be reported as (ppm as CaCO3). Their actual concentrations as Ca or Mg is probably around 46 and 2 ppm, respectively.

 

[DSmith]

100% RO for sparge is always a good idea to keep the sparge pH low. The tap water for mashing may make beers made with darker malts well, but should be cut with RO water or use 100% RO water for beers with lighter kilned malt.

I've been using 100% RO water for mashing and sparging and have been purposely been brewing lighter beers to stay away from mixing tap water back in for higher mash water alkalinity (tap water alkalinity is about 350 ppm as CaCO3) and they’re consistently needed some acid for mash pH control. Brewing ambers and browns now takes 25% tap water and very minimal/no acid to get a 5.4-5.5 mash pH (room temp) but am still using 100% RO water for sparging.

Learning to control alkalinity by mixing RO & tap water based on the ingredients and minimizing correction by acid has been made pretty simple with some of the pH modeling spreadsheets. A calibrated pH meter is always useful to check the spreadsheets prediction, correct and learn.

 

[Wynne-R]

Hmmnn. . Interesting about the cations. I thought it was weird the calcium is at or above the bicarb level. The report says bicarbonate 99-123 ppm, calcium 89-142 ppm. I have a call into the water dept. I’m sure they love calls from homebrewers. She just called, You’re right. They’re going to fix that next year.

I figured the alkalinity was high, which is why I started playing with dilution. I have a buddy who says “the solution to pollution is dilution.”

My question is what is the difference between RO sparge and like 50/50 for everything? My mash efficiency is good, so I guess maybe I’m doing it right with the soft sparge.

Thanks Martin, for helping me with the chemistry. It’s been too long since college for me to remember how to deal with moles, mEQ and pK. I’m working on it though.

 

[MNDan]

I've been using 100% RO water for mashing and sparging

I hope you've been adding some CaCl - you shouldn't brew with water that doesn't contain at least some calcium.

Regarding sparging with pure RO water - no worries - I don't think you'd ever see a pH above 6 for any beer sparged with RO water. If you are worried, add a touch of lactic acid to it.

 

[DSmith]

I hope you've been adding some CaCl - you shouldn't brew with water that doesn't contain at least some calcium.

Regarding sparging with pure RO water - no worries - I don't think you'd ever see a pH above 6 for any beer sparged with RO water. If you are worried, add a touch of lactic acid to it.

Good point, all water is treated the same per gallon the for CaCl2 and CaSO4 additions for the recipe. If the mash water has some tap water mixed in then it will have slightly different concentrations as the 100% RO sparge water, but not significantly different. Browns & stouts are the only ones I've mixed tap water into the mash yet, all other beers work fine with 100% RO mash & sparge water (always with CaCl2, sometimes CaSO4) with acid malt used when needed.

 

[Wynne-R]

You guys have some seriously gnarly water. I appreciate the benefit of your experience with “water” that will probably stand up a spoon.

How much Calcium do you use? I have read things that indicate the minerals in the mash may be adequate. What’s the downside to too little Calcium? Is it the mash or something else?

 

[ajdelange]

A while back I diluted my carbon block filtered tap water with two gallons of RO. I didn’t notice any change so I forgot about it. Lately I’ve been using three gallons of RO sparge in to four gallons of mash and it’s remarkable. The beer is softer and much less astringent. It’s a pale ale with ten pounds of grain in about 4 ½ gallons. ColorpHast indicates 5.1 in to the brew kettle.

I kinda get the conventional wisdom is to treat all the liquor the same, but my informal results fly in the face of that. An old boss used to say I don’t understand all I know about this. Can somebody tell me what I'm doing?

I'm not 100% clear on what you are doing but I believe you are using more dilution RO water than previously and have noticed an improvement in the beer. This is not surprising. If I am interpreting correctly you have effectively reduced alkalinity which leads to lower mash pH (at a faster rate than reducing the calcium increases it). This results is beers with 'brighter flavors'. You are also reducing sulfate. This may well be responsible for the reduced astringency but another possible cause of this is less alkalinity in the sparge water may be resulting in reduced phenol extraction.

 

[Wynne-R]

Hi AJ. What I’m trying to say is that when I used 50% RO in the mash it didn’t do anything. When I used 100% RO in the sparge there was a marked decrease in astringency.

Here’s what the water dept says:
pH 8.2-8.4
Bicarbonate 99-123
Calcium as CaCO3 89-142
Magnesium as CaCO3 4-8
Chloride 16-33
Sodium 14-22
Sulfate 23-36
TDS 210-245
Total alkalinity as CaCo3 99-123
Total hardness as CaCo3 85-168

I am currently using 4 gallons in the mash and three in the sparge. The RO is from one of those drive-up parking lot things. They do ion exchange and carbon block ahead of the RO so I’m guessing it’s pretty close to zero across the board. So I should be rockin’ 4/7 of those numbers overall.

 

[jetmac]

This brings an idea to mind. I almost always use a 50/50 mix for brewing. I wonder what effect it would have if I used just tap water for mashing(50%) then all RO water in the sparge(50%)? Still using a 50/50 mix for the boil just not mixing it for the mash

 

[ajdelange]

Hi AJ. What I’m trying to say is that when I used 50% RO in the mash it didn’t do anything. When I used 100% RO in the sparge there was a marked decrease in astringency.

Got it. Yes, you are carrying a fair amount of alkalinity but not a whole lot. If you noticed a reduction in astringency when using RO water that certainly suggests that lauter pH was rising too high and that using RO fixed it. But I would expect some effect from diluting the mash water as well. You have enough sulfate that reducing it by 50% ought to make a perceptible difference in the way hops are perceived. Also reducing the alkalinity to 50 - 60 is getting it down to a sort of maximum acceptable level for most beers. I usually suggest for water like yours a dilution to the point where alkalinity is even lower than that. See the Primer.

 

[Wynne-R]

Thanks AJ, I have read the primer many times, even read all the posts twice. I have a basic grasp of the chemistry, and now I’m learning about the effects of different ions on(in?) my beer. As Revvy says, it’s cooking.

The conventional wisdom in my area is that our water is pretty good. I don’t know of anyone else treating the local water. I was really surprised by how much room there is for improvement, and apparently I have a ways to go. Now I need to get some more jugs.

Just ‘cause your beer is good doesn’t mean it can’t be better.

Thanks again AJ and Martin and everybody else for sharing their time and their talent. Y’all rock.