Dealing with Rochester MN water

[z-bob]

I didn't see an active water thread that I could piggyback on without hijacking it. So here's another one.

I've been brewing pretty good beer by diluting my local tapwater with RO water, and adding Sauermalz to the grist. I'm trying to get away from using any RO water (it's a personal challenge; it doesn't have to make sense.)

I've started using lactic acid to acidify the mash, but it takes a *lot* of lactic acid to neutralize all the bicarbonate . I may switch to phosphoric acid; I have a quart in the "buy it later" section of my Amazon shopping cart.

Here's what my water looks like according to the annual city water report, in ppm. The anions and cations don't balance so the numbers are suspicious, but the alkalinity seems to be about right:

Ca++ 72, Mg++ 25, Na+ 10, Cl- 5, SO4-- 46, HCO3- 317, pH 7.5

I've read somewhere that the taste threshold for lactate is about 300 to 400 ppm. I brew in 4 gallon batches, so in round numbers that's about 15.2 liters plus another 3.8 liters lost to grain absorption. If I add 7 ml of 88% lactic acid to the mash, that's about 324 ppm, right?

7ml * .88 / 19000ml = 3.242e-4

7 ml of acid is enough to drop the pH to about 5.4 for a typical grain bill and a 4 gallon mash. 6 ml would get me somewhere around pH 5.5. If I sparge with another 2.5 gallons of water, do I really need to acidify it too if I use warm water instead of hot? (say, 100°F)

To acidify the entire 6.5 gallons with lactic acid, according to the brewersfriend mash chemistry calculator, takes 9.5ml. That yields about 440 ppm of lactate, which is higher than I want to go.

I think where I will end up eventually is using Sauergut to acidify the mash, and phosphoric acid to acidify the hot sparge water. I'm going to try lactic acid and tartaric or citric acid in my next brew session.

 

[Silver_Is_Money]

Sauergut is essentially lactic acid, but with the added presence of active lactobacillus (that is not present within 88% lactic acid) it will have a far greater chance of flavor tainting your beer than will 88% lactic acid.

Around a decade ago Kai Troester (Braukaiser) tested a range of different beers with lactate taken well beyond 400 ppm, and he and his group of taste testers discovered that it takes generally well more than 400 ppm before its presence can be detected. One of his closing remarks is that acidulated malt can freely be used at up to 8% of the grist bill by weight without worry. For 12 lbs. of grist, that is nearly 16 ounces.

And on the Weyermann website it is stated that the average beer drinker prefers the taste of beers acidified with acidulated malt to other less flavorful acid alternatives (including one might presume, lactic acid).

 

[z-bob]

Sauergut is essentially lactic acid, but with the added presence of active lactobacillus (that is not present within 88% lactic acid) it will have a far greater chance of flavor tainting your beer than will 88% lactic acid.

Around a decade ago Kai Troester (Braukaiser) tested a range of different beers with lactate taken well beyond 400 ppm, and he and his group of taste testers discovered that it takes generally well more than 400 ppm before its presence can be detected. One of his closing remarks is that acidulated malt can freely be used at up to 8% of the grist bill by weight without worry. For 12 lbs. of grist, that is nearly 16 ounces.

And on the Weyermann website it is stated that the average beer drinker prefers the taste of beers acidified with acidulated malt to other less flavorful acid alternatives (including one might presume, lactic acid).

With this water, it takes over 10% acid malt to get the pH down to 5.4 with light-colored grist if I want to treat all the liquor. That's why I asked about sparging with warm water instead of hot. Not sure if that will prevent tannin extraction if the pH is 7.5, but I think it might.

 

[ajdelange]

That's pretty alkaline water; about 5 mEq/L. You've also got about 3.5 mEq/L calcium so this looks like a case where you could supplement the calcium by about 1.5 mEq/L (you've got headroom in chloride, and, if you are a sulfate lover, that ion as well) and heat the water precipitating most of the alkalinity. You'd have about 1 mEq/L of that left and 1 mEq/L calcium left as well. You would, thus, need about 1/5th as much acid or sauermalz.

 

[z-bob]

Thanks AJ, I may try that. I also finally ordered a pH meter (Hach PP+) so I can see what my acid additions are really doing instead of blindly following the water report and the brewersfriend water calculator.

I wonder if the missing cations are Fe++?

 

[ajdelange]

There's a simple test. Aerate some of the water thoroughly. If it goes from clear to gray or yellow or brown that's iron. If it doesn't change from clear then run it through a filter made from a piece of paper tower folded into half and then half again. Open up one side to make a sort of funnel and if you have a funnel handy put the paper towel into it. Pour the aerated water through. A brown or orange stain on the towel indicates iron.

 

[z-bob]

I'm brewing for the first time with a pH meter. I added the calculated amount of lactic acid (6 ml) to lower the mash pH to 5.50 with my grain bill and 4 gallons of water. I checked the pH and it's 5.85. What does that tell me? That my water is more alkaline than the water report says, or that my lactic acid is old and lost strength. (does it do that?) I'm going to leave it alone for this batch; I've gotten good conversion using this much acid when "flying blind". But is this enough information to know how much to adjust next time? I'm okay with it taking 2 or 3 tries to sneak up on the exact number, as long as I don't ruin any beer along the way.

I'm going to acidify the sparge water with phosphoric acid. Haven't gotten that far yet, but I will measure the pH of that too and see how far off it is from where I think it should be.

It is tempting to add about 2 ml of phosphoric acid (85%) to the mash and see what happens.

Edit: the acidified sparge water was supposed to be 5.4 and it measured 5.86. Part if this might be because I only did a 1-point calibration of the meter, using the 7.00 buffer packet that came with it. I've ordered some 7 and 4 buffers, and they get here in a day or two.

 

[Silver_Is_Money]

I'm brewing for the first time with a pH meter. I added the calculated amount of lactic acid (6 ml) to lower the mash pH to 5.50 with my grain bill and 4 gallons of water. I checked the pH and it's 5.85. What does that tell me?

What are the detailed specifics of your batch as to grist quantities and mineralization? What are the specifics of your strike water? What software did you use to target the 5.5 mash pH?

 

[z-bob]

What are the detailed specifics of your batch as to grist quantities and mineralization? What are the specifics of your strike water? What software did you use to target the 5.5 mash pH?

The city water report is at the beginning of this thread. It says the alkalinity is 317 ppm HCO3-. I did not add any minerals, just acid. (I'm going to add 1 gram of table salt to the boil)

The grist was:
6.25 lbs 2-row pale malt
6 oz Munich, 10°L
6 oz Crystal wheat malt, 45°L

4 gallons of strike water, just under 2.5 gallons of sparge water (it's a 4 gallon batch) I used the water chemistry calculator at brewersfriend.com. Gotta go, the mash timer is going off.

 

[Silver_Is_Money]

Based upon running the numbers through my 'Mash Made Easy' spreadsheet, 6 mL of 88% lactic acid in the mash (or in the strike water) seems about right, but I suspect that crystal wheat malt may not carry near the same level of acidity as for crystal barley malt (though there are only 6 ounces of it, so the impact of this may not be severe). What brand of 2-Row did you use? What is its nominal Lovibond color?

It is of course highly possible that your city water report is an average of readings taken over perhaps up to a one year period, and that at any given moment in time it may vary in mineralization and/or alkalinity to some nominal +/- degree which may be appreciable enough to contribute to your mash pH anomaly.