Is this Bru'n Water profile correct?

[jwelch1103]

I am hoping I can get some feedback here. I've been using Bru'n water to build water profiles for my beers for a couple of years now and am somewhat comfortable using it.

I am making my first very dark beer (EBC 73.8) while building a water profile and am surprised by how acidic these dark malts make the mash. When I added the malts into the grain bill the unadjusted ph is predicted to be 4.3 and to get this up in the 5.4 range I have to add what seems to me to be a lot of baking soda, 1.8 grams per gallon. The overall finished water has only 74 ppm of Sodium which in my understanding is not too high and I was able to adjust the other minerals close to what the profile calls for (about 15-20% up or down depending on the mineral).

So, my question is: does this seem out of kilter with this baking soda addition?

 

[jwelch1103]

 

[ScrewyBrewer]

Without knowing your grain bill, types and amounts, its really impossible for me to tell. I guess you could use RO or distilled water, or reduce the amount of dark grains.

 

[jwelch1103]

I am using 100% RO/DI water, here's the grain bill.

 

[mabrungard]

Wow, I didn't know there was a maltster producing a crystal malt that dark. I'm not sure how its acidity will actually stack up, but its probably inching into the roast acidity. Given the color and the assumptions on acidity vs color for crystal malts, I'm guessing that the model is OVERPREDICTING the acidity and you should assume that the dark crystal is actually behaving as a roast malt. That will reduce the predicted acidity and lessen the need for baking soda and its alkalinity.

An overall sodium content of 74 ppm isn't too bad, but I wouldn't want to go any higher.

 

[ScrewyBrewer]

If using RO water I would have expected your 'existing water profile' minerals to be close to zero. Is your source water so high in minerals that the RO water output still has a higher mineral ppm?

 

[jwelch1103]

Wow, I didn't know there was a maltster producing a crystal malt that dark. I'm not sure how its acidity will actually stack up, but its probably inching into the roast acidity. Given the color and the assumptions on acidity vs color for crystal malts, I'm guessing that the model is OVERPREDICTING the acidity and you should assume that the dark crystal is actually behaving as a roast malt. That will reduce the predicted acidity and lessen the need for baking soda and its alkalinity.

An overall sodium content of 74 ppm isn't too bad, but I wouldn't want to go any higher.

Martin,
I don't want you to think I'm trying to argue with you because I'm not, but I want to get my head around this, so with that in mind:
If I assume it is more like a roast malt (that thought had crossed my mind, BTW) and change the grain type for the Patagonia Crystal 190L to roast malt on the grain bill page the ph prediction drops to 5.19 so I'm just a bit more confused now.

If it is overpredicting the acidity then perhaps I could tweak the baking soda level down a bit, say until it predicts a 5.38 (or so) ph. If I did that and the program is overpredicting I might end up in the proper range. I'm scratching my head here. I've never had to adjust a mash ph before and IIRC have heard that it is difficult to do properly and completely.

How confident are you that the program is overpredicting in this instance? Were you making this beer what would you do? Thank you for your input here.

 

[jwelch1103]

If using RO water I would have expected your 'existing water profile' minerals to be close to zero. Is your source water so high in minerals that the RO water output still has a higher mineral ppm?

There is another page in this spreadsheet that allows one to specify how much to dilute the existing water with RO water and then uses those values. I have specified 100% dilution here. Since I always use RO water I leave this at 100% dilution.

Here it is for this beer:
View attachment 548909

 

[mabrungard]

If I assume it is more like a roast malt (that thought had crossed my mind, BTW) and change the grain type for the Patagonia Crystal 190L to roast malt on the grain bill page the ph prediction drops to 5.19 so I'm just a bit more confused now.

That's odd. I just performed a quick check of pH impact by dialing up 190L as the color and then switched from Crystal to Roast and back. The pH prediction is lower when I select Crystal.

 

[mabrungard]

I found the problem! The calculation converting EBC to L is incorrect in Bru'n Water. I've got some correcting to do. In the interim, I recommend that you use L color for your malts instead of EBC.

 

[ScrewyBrewer]

I noticed that too Martin. 190 Lovibond is equal to 190 SRM or 374 EBC, although I never work with anything other than Lovibond myself I wasn't too sure.

 

[Silver_Is_Money]

190L = 257 SRM = 506 EBC

https://www.brewtoad.com/tools/color-converter

Give 'Mash Made Easy Metric' a spin.

 

[mabrungard]

OK, I was wrong that I was wrong. It turns out that I was using the same incorrect conversion from EBC to Lovibond that Screwybrewer used. EBC is NOT equal to 1.97xL. EBC is equal to 1.97xSRM. SRM and L are not equal and they diverge substantially at darker color.

The correct conversion is EBC is equal to 2.66xL - 1.5. That is the conversion that is used in Bru'n Water. So the 190L crystal malt has an EBC rating of 504. When you insert that into the Grain Bill Input sheet and then toggle between Roast and Crystal malt settings, the Roast setting does show the pH as higher.

 

[ScrewyBrewer]

Adding to the confusion.... the Brewtoad calculation, which I referred to at first, is drastically different than the Aussie brewer's....

http://pint.com.au/calculators/maltcolour/


Brewtoad I believe correctly calculates 190L as SRM 256 and EBC 506

 

[ajdelange]

That's because there is no conversion between Lovibond and SRM. Well, there is, of course, but only the Tintometer people know what it is and they aren't talking. In researching this for the Bamforth book I e-mailed them saying that I was going to write about this and wanted to get it right which I could only do if they told be how they map from a spectrum to a number which is the way their instruments now work but I was ignored.

I was able to find an old paper in which the absorption spectra of the Lovibond glasses was given. They do not match beer spectra (which would be OK if the colors in Lab space were metameric to beer colors but they aren't). The best you can do is collect your beer's spectrum, calculate the Lab color, and interpolate between the colors of the two closest Lovibond glasses. This works OK for light colored beers (the scaling factor in the SRM method was chosen to make SRM correspond to Lovibond for the exclusively light colored beers brewed in the days the SRM was invented) but falls apart at denser colors.