Experienced with water adjustments, but doing my first decoction mash. Help me get the right mash pH

[HausBrauerei_Harvey]

I have been using brunwater for a while and understand my water and the adjustments well. Trouble is i'm attempting my first decoction mash for a german pilsner this weekend and am unsure how this will affect my typical water adjustments.

I'm using weyermann premium pilsner malt so i'm skipping the acid rest and going to dough in thick at 122F, raise to 147 with a boiling water infusion, then decoct to get to 156F, and decoct to get to a mash out at 168. I will then batch sparge like normal.

I have accurate quarterly water reports going back 5 years from my city, so I know my water on brew day will be 42ppm Ca, 108ppm sulfate, 47ppm Cl, 45ppm bicarbonate, 13ppm total alkalinity, just a bit of Na and Mg. Thus I really only need to worry about acid additions.

using brunwater the way I have been I calculated I need to add 8ml/gal to my mash water to hit a mash pH of 5.33. I just read that decoction can tend to lower mash pH, so I'm looking for some guidance here for how to use brunwater when decocting, or even a rule of thumb, e.g. decoction tends to lower pH 0.1 for each decoction, so then I can account for that in the acid addition.

hopefully someone out here has an answer for me.

 

[JimRausch]

I've been doing decoction mashes for years (usually just one from 145-> 155). Have also used Brunwater for years. I managed my water additions without being concerned about what the decoction might do to pH. This past year, I finally bought a pH meter and checked the pH before and after my decoction. No change in pH. So unless AJ or Martin pipe in with other info., I say you are fine.

 

[cire]

Differences in mash pH from single temperature infusion to temperature programmed and decoction mashes have been observed. There is a section on this in the paper linked below beginning page 99.

http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1975.tb03668.x/epdf

 

[ajdelange]

It's reasonable to assume that the reactions which continue precipitation of appatite and carbonate in the kettle would also take place in the decoction vessel and, as I recall from the days when I used to brew with liquor containing calcium, that's what happened (pH went down after each decoction). When I discovered how much better my lagers were when brewed with RO water and just a bit of calcium chloride (no alkalinity/bicarbonate) the pH only changed slightly (0.01 or 0.02) from the 20 - 30 min post dough in reading with the decoctions and that change was upward.

 

[HausBrauerei_Harvey]

It's reasonable to assume that the reactions which continue precipitation of appatite and carbonate in the kettle would also take place in the decoction vessel and, as I recall from the days when I used to brew with liquor containing calcium, that's what happened (pH went down after each decoction). When I discovered how much better my lagers were when brewed with RO water and just a bit of calcium chloride (no alkalinity/bicarbonate) the pH only changed slightly (0.01 or 0.02) from the 20 - 30 min post dough in reading with the decoctions and that change was upward.

Thanks A.J., I understand what you are saying, the volume of water in the wort getting decocted would see the equivilent reduction in bicarbonate and appatite i'd get for boiling that volume of water. So if I interpret this correctly I come to the following conclusion: my water is low in carbonate to begin with (45ppm), and i'm treating the liquor with the right amount of acid according to brunwater to neutralize the alkalinity of my water to get my mash pH where I want before I pull my first decoction, then I should not expect a significant change in the mash pH when decocting correct?

Thanks!

 

[ajdelange]

That's what I have always seen and I would expect you to see something similar, the theory suggests that this will be the case (unless there is a lot of calcium present which you didn't mention, and JimRausch has had similar experience.

 

[HausBrauerei_Harvey]

Ok many thanks. I listed my water profile in the first post, sorry it's a bit long. I'm currently at 42 ppm Ca 100ppm SO4, 50ppm Cl, so i think it should be perfect for my intended beer, a North German Pils. Many thanks for your time and help everyone!

 

[ajdelange]

Sorry I missed that (or more probably forgot it) but at that level of calcium I wouldn't expect to see a drop after the decoctions. Of course one of the interesting things about brewing is that it often presents unexpected surprises. Other brewers' experiences and the science provide us invaluable guidance but not perfect predictions of what's going to happen.

 

[HausBrauerei_Harvey]

I've been doing decoction mashes for years (usually just one from 145-> 155). Have also used Brunwater for years. I managed my water additions without being concerned about what the decoction might do to pH. This past year, I finally bought a pH meter and checked the pH before and after my decoction. No change in pH. So unless AJ or Martin pipe in with other info., I say you are fine.

One last question: I'm looking at Braukaiser's Hochkurz decoction schedule. for simplicity i'd like to just do a boiling water infusion to get from 133 to 142, i'm unsure how to deal with the acid additions when essentially splitting my typical mash liquor volume into a 2/3 (initial) 1/3 (step to 143) ratio. With brunwater I can calculate an acid addition for a single hot liquor addition mash. I think I remember hearing before not to add acid at those low rest stages. I appreciate any info you can give me, and thanks so much for your help, i'd love to get a nice decoction process ironed out for my german lagers, which have been good but are missing that little something you get in authentic versions, which I think must be melanoidens from the decoctions.

 

[ajdelange]

With alkalinity of 13 (0.25 mEq/L) you are not adding acid for the sake of the water but only for the grains. Thus all you have to do really is add 2-3% of sauermalz to your grist and you should be in good shape. It is best to check on this by doing a test mash. If the pH is lower than you like use less sauermalz. If high, use more. Sauermalz is preferred to liquid acid by some as it is a malt and thus adds some of its own subtle malt character to the beers. Others say they can't tell a difference when sauermalz is used (Triangle Test time!).

While checking your reported water ion concentrations I noticed that you have a lot of sulfate. That often does not go well with noble hops. You might want to try a batch or two with say 1:2 or 1:3::tap:RO dilution (might as well use all RO in the latter case) to see if you like the beers better.

 

[HausBrauerei_Harvey]

. Thus all you have to do really is add 2-3% of sauermalz to your grist and you should be in good shape.

While checking your reported water ion concentrations I noticed that you have a lot of sulfate. That often does not go well with noble hops. You might want to try a batch or two with say 1:2 or 1:3::tap:RO dilution (might as well use all RO in the latter case) to see if you like the beers better.

I tried saurmaltz once but didn't get the pH change I calculated with brunwater, so I've moved to phosphoric acid and really like using that. So if I were using liquid acid how would you advise me to proceed?

I live in Colorado so our water changes alot through the seasons, it has the most sulfate of the year right now as it's coming from reservoirs, it gets close to pilsn water with the spring runoff. I used to live in germany and loved hoppy north german pilsners, Flensburger and Jever pilsner were my favorites, the Jever profile in brunwater it's actually higher in sulfate. I'm still trying to get my version of those beers nailed down though, maybe I have been using too much sulfate as you suggest, last time I targeted 150ppm, this time i'm much closer to the Jever profile (which is 46ppm Ca, 75ppm SO4, 30ppm Cl, 60ppm bicarbonate)

 

[ajdelange]

I tried saurmaltz once but didn't get the pH change I calculated with brunwater,

Not surprising.

...so I've moved to phosphoric acid and really like using that. So if I were using liquid acid how would you advise me to proceed?

Use a calculator or spreadsheet to calculate the amount of the acid it thinks you need with the water's alkalinity set to 0. New set you water's alkalinity to 0 by acidifying it to mash pH. Next make a test mash with a modest portion of your grist and the calculated (scaled, of course) acid addition. Check pH and revise the acid addition. Try again until you feel you are close enough.

I live in Colorado so our water changes alot through the seasons, it has the most sulfate of the year right now as it's coming from reservoirs, it gets close to pilsn water with the spring runoff. I used to live in germany and loved hoppy north german pilsners, Flensburger and Jever pilsner were my favorites, the Jever profile in brunwater it's actually higher in sulfate. I'm still trying to get my version of those beers nailed down though, maybe I have been using too much sulfate as you suggest, last time I targeted 150ppm, this time i'm much closer to the Jever profile (which is 46ppm Ca, 75ppm SO4, 30ppm Cl, 60ppm bicarbonate)

If you like beers brewed with sulfate then ignore what I said. At the same time it never hurts to experiment with more or less of something in order to see if you can get something you like even better.

 

[HausBrauerei_Harvey]

Not surprising.
Use a calculator or spreadsheet to calculate the amount of the acid it thinks you need with the water's alkalinity set to 0. New set you water's alkalinity to 0 by acidifying it to mash pH. Next make a test mash with a modest portion of your grist and the calculated (scaled, of course) acid addition. Check pH and revise the acid addition. Try again until you feel you are close enough.

Sorry to keep pestering you but i'm not 100% clear how this applies to my question of a doing one step of the 3 step mash profile with infusion water. I think you are suggesting that when doughing in I use the calculated amount of acid in the liquor to get to the target mash pH. Then with the infusion I just add the correct amount of acid to neutralize the water alkalinity, similar to my batch sparging liquor. Is this correct? I can always just decoct a portion of the mash to get to that second step if thats easier.

 

[ajdelange]

Sorry to keep pestering you

Not a problem!

but i'm not 100% clear how this applies to my question of a doing one step of the 3 step mash profile with infusion water. I think you are suggesting that when doughing in I use the calculated amount of acid in the liquor to get to the target mash pH.

What I am trying to do is remove the need for calculation and the measurement (alkalinity) that is required to get a correct result from the calculation. Ordinarily a laboratory adds acid to a sample of your water to see how much it takes to lower the pH of a liter of it to 4.5, multiplies that by 50 and reports this as alkalinity. It is then the job of whatever calculator you use to calculate how much acid is required to lower the pH of a liter of water to your specified mash pH, multiply that by the liters of water you intend to mash with and and report that to you as part of a total acid requirement the other part of which the acid required to lower the grains to the desired pH. As none of the spreadsheets I have looked at ask you to specify the source water pH none of them can give you an accurate result, though in most cases it is probably accurate enough as long as the correct alkalinity number is added. Thus a bigger problem with this approach is that the alkalinity of what is coming out of your tap is not the same as what last winter's Ward Labs analysis reports. The way around this is to make an alkalinity measurement yourself each time you brew, make the calculations yourself using an accurate calculator (the formulas are in a Sticky here). But that's extra work and you don't have to do any of it if you use water with 0 alkalinity WRT your desired mash pH. This water comes from two sources: RO/DI water is one. The other is water to which you have added sufficient acid to bring its pH to the target. Once you have treated the entire volume of your brewing water its alkalinity is no longer of concern. You only need to worry about the acid requirements of the malt. If you are comfortable with the accuracy with which the brewing software estimates these you need only tell the program what the malts are specifying 0 alkalinity and the program will tell you how much acid to add assuming that you are using water of 0 alkalinity which you are. Add that extra acid to your strike water and the pH should arrive close to the desired pH if you have done your calculations accurately or tweaked the malt acid addition as the results of a test mash. Thereafter you may add the treated water to this mash for infusion, to make up the water lost during a decoction, to thin the mash for transfer to the lauter tun, for sparging and to make up volume after the boil. No additional acid need be added to this water for any of these purposes.

Then with the infusion I just add the correct amount of acid to neutralize the water alkalinity,

If you proceed as described above the water alkalinity has already be neutralized and is suitable for use at dough in, for infusions etc.

similar to my batch sparging liquor.

All the alkalinity has been neutralized and the water is indeed also ready to be used for batch sparging.

I can always just decoct a portion of the mash to get to that second step if thats easier.

I can't immagine a decoction being easier than this!

I know this must be difficult to understand because nobody seems to understand it. Unfortunately the only reason for this I can think of is that I am not explaining it very well because it is actually really quite simple.

 

[HausBrauerei_Harvey]

I know this must be difficult to understand because nobody seems to understand it. Unfortunately the only reason for this I can think of is that I am not explaining it very well because it is actually really quite simple.

A.J. Thanks so much, this finally clicked for me! I will acidify the first water addition which will not only neutralize the waters alkalinity but also lower the grains to my desired pH (5.3). All subsequent water additions (first infusion and batch sparge) will only have enough acid added to neutralize the alkalinity.

Thanks again for your time and all you do for the community to help us better understand this sometimes confusing subject!