Low Mash pH Calc and Weird Water Profile (Brewers Friend + Bru'N Water)

[Obese Chess]

Good afternoon!

I am a few days from my first ever brew day and trying to get the last bits of information dialed in on a Robust Porter whose recipe I keep changing from its original (lol). I plugged my grain bill into Brewers Friend and was given a potential mash pH of 4.1 without inputting any sort of water profile. Realizing this to be impossible, especially because removing 3/4lbs of chocolate malt from my 13lb grain bill bumped me back up to 5.8, I could have just ignored it - but instead I started messing around with water chemistry, despite multiple local homebrewers, the guy who originally wrote the recipe, and my LHBS telling me that our water here is just fine and not to mess with it (I still may do this, but I've got time to kill).

I got the following water profile from my supplier:

Ca+2 and Mg+2: Calcium and Magnesium analysis determines water hardness. Our water is very soft, with hardness ranging from about 18 to 30 ppm.

Na+:11 ppm.

Cl-: 2 ppm.

SO4-2 is sulfate and is not something that we analyze for.

HCO3-: Bicarbonate analysis determines alkalinity. Our water ranges from about 23 to 30 ppm.

pH runs about 7.7.

I did some more digging and found other water profiles in my area putting our sulfate at 5 ppm, so I'm using that as my value. For everything else I'm just taking the midpoint in those ranges (24ppm for Ca+2 and Mg+2 and 26.5ppm for HCO3-). When I plug this into Brewers Friend, my mash pH goes up to a whopping 4.18. In Bru'N Water, these inputs show up as being "unbalanced" but I can't figure out why.

I imagine my "averaging" - or "averaging" on the part of the utility company - is what's throwing these numbers off. What am I doing wrong and how can I fix it? For what it's worth, if I plug this same recipe into Beersmith I get a mash pH of 5.48 or something around there.

Thanks!

 

[Gnomebrewer]

Hmmm, I suspect they're giving you 'hardness as CaCO3' rather than Ca + Mg in ppm. If we assume all of your hardness is Calcium (which it won't be, but it's so soft it won't really matter) then your Calcium is about 10ppm - that should give you something closer to balanced (without actually calculating it).

 

[Gnomebrewer]

Also, can you post your grain bill? I can't see any sensible recipe getting a 4.1 mash pH.
At the very least, you should look to add some Calcium in to your water for all beers. You will probably also need a bit of bicarbonate for this one (baking soda works well).

 

[Obese Chess]

For a 5-gal batch of porter:
9lb Maris Otter
1lb Munich Light
1lb Flaked oats
.5lb Crystal 60L
.25lb Carapils
.25lb Chocolate Wheat

That input gives me a mash pH in Brewers Friend of 5.58.

When I add 1lb of Chocolate Malt, regardless of brand I use, it drops all the way to 4.11. This seems... unlikely.

 

[balrog]

and adding 1 whole pound of chocolate malt is just ... wow.

 

[Obese Chess]

That's about 8% of the total grain bill. I haven't had this beer in many years but don't recall the chocolate malt taste being too overpowering at 3/4lb and the notes I have say "maybe add a little more chocolate malt next time."

I'm using a German chocolate malt of 350L, not the really heavy-duty 600L+ British ones, for what that's worth.

The way I see it, the worst that happens is I learn something about chocolate malt in the mash.

 

[Gnomebrewer]

When I add 1lb of Chocolate Malt, regardless of brand I use, it drops all the way to 4.11. This seems... unlikely.

It's extremely unlikely - Chocolate malt only has a DI mash pH in the 4.3 to 4.5 pH range (according to 'How to Brew'), so it can't bring the pH of a buffered wort down to 4.11. According to Mash Made Easy, that grainbill and water would give a mash pH somewhere around 5.30 (but depends a bit on specific grains used). I'd estimate a mash pH in the 5.1 to 5.2 range (I'd use 2 grams of baking soda in the mash).

 

[Obese Chess]

Cool. Beersmith, without loading a water profile, was giving me a mash of around 5.5 so that seems to track. I just can't figure out why Brewers Friend is giving me so much grief about that one ingredient. As the water is so soft and many famous stouts are made with "hard" water, is there a benefit to adding any additional minerals, or should I KISS for my first batch (insofar as "making an all-grain porter for your first ever brew" is simple)?

 

[Gnomebrewer]

It's simple to add some salts to your water. Add a teaspoon of Calcium chloride to your mash water plus a teaspoon directly into the boil. Add 2g of Baking soda (Bicarb soda) to the mash water only.

 

[Gnomebrewer]

I just put all of that info into Brewer's friend and it gave a 5.43 mash pH. That included over estimating the colour of the choc malt at 1000L. Can you show a screenshot of your grainbill input in Brewersfriend, as I have?

 

[Obese Chess]

Your screenshot helped me solve the problem! For some reason, Brewer's Friend is classifying the chocolate malt as a "base malt." If I change it to "roasted malt" in the water calculator the pH goes up to 5.48. I have to add it as a custom fermentable to change this and then I'm in business! Thank you!