ph and late addition of dark grains

[bg1414]

I've read a lot about adding dark grains late in a mash, but I'm still not sure about ph adjustment when doing this. Please chime in on my method.

I made a water profile for the full grain bill with a total mash water volume of 6 gallons. I made another profile excluding the dark grains with half the water (3 gallons). The main mash has pretty much half the salt additions to get a good ph level compared to after adding dark grains. So the plan would be to mash in with 3 gallons and the salt additions needed. Then add the dark grains, 3 more gallons and the rest of the salts/baking soda to maintain that ph.

Is this correct? I have seen some stuff that when adding dark grains late after conversion that this ph adjustment isn't needed. If that is the case then can I just mash a 6 gallons and then add any baking soda to the kettle?

 

[acidrain]

Have you considered steeping the dark grains while the main mash is working, then just adding that wart to the main mash wort?
I've never done it, but I understand this is one option. I would assume that the steeping is done with water additions.

 

[bg1414]

Have you considered steeping the dark grains while the main mash is working, then just adding that wart to the main mash wort?
I've never done it, but I understand this is one option. I would assume that the steeping is done with water additions.

I have heard of that as an option.

 

[MagicMatt]

I don't think you need to worry about adjusting the salts or water after you steep. I've often withheld my roasted grains until late in the mash and never needed to adjust anything.

Calculate your mash volume using the full grain weight and your desired mash thickness (i.e. 1.25qt/lb, etc). But when you build your water profile and calculate your salt additions, do not add the dark grains to that calculation. Basically make it so the thickness is correct after you add the dark grain, but the pH is correct before you add them.

Let's say your grain bill is 14 lbs, with 1lb of roasted grain.

So your mash thickness for 14 lbs @ 1.25qt/lb would require 17.5 qts.

However, you're actually only mashing with 13 lbs and the same 17.5 qts, so your realized mash thickness is 1.34qt/lb (until you add the roasted grain).

So your water calculations should only have the 13 lbs of grain and the 17.5 qts of water, and let's say that gets you a pH of 5.9. You determine that you'll need 4g each of CaCl and Gypsum to reach 5.2pH.

So when you mash, you'll have 17.5qts of water, 13 lbs of grain, and 8g of salts. Let that go for 40-45 minutes or so and then add your dark grain. The mash thickness will now be 1.25qt/lb, and the pH may drop slightly but shouldn't be an issue because the main conversion of your grains has already happened. The dark grain at this point is more for color and less about conversion, so no need to worry about the pH being slightly low at this point.

 

[bg1414]

I don't think you need to worry about adjusting the salts or water after you steep. I've often withheld my roasted grains until late in the mash and never needed to adjust anything.

Calculate your mash volume using the full grain weight and your desired mash thickness (i.e. 1.25qt/lb, etc). But when you build your water profile and calculate your salt additions, do not add the dark grains to that calculation. Basically make it so the thickness is correct after you add the dark grain, but the pH is correct before you add them.

Let's say your grain bill is 14 lbs, with 1lb of roasted grain.

So your mash thickness for 14 lbs @ 1.25qt/lb would require 17.5 qts.

However, you're actually only mashing with 13 lbs and the same 17.5 qts, so your realized mash thickness is 1.34qt/lb (until you add the roasted grain).

So your water calculations should only have the 13 lbs of grain and the 17.5 qts of water, and let's say that gets you a pH of 5.9. You determine that you'll need 4g each of CaCl and Gypsum to reach 5.2pH.

So when you mash, you'll have 17.5qts of water, 13 lbs of grain, and 8g of salts. Let that go for 40-45 minutes or so and then add your dark grain. The mash thickness will now be 1.25qt/lb, and the pH may drop slightly but shouldn't be an issue because the main conversion of your grains has already happened. The dark grain at this point is more for color and less about conversion, so no need to worry about the pH being slightly low at this point.

That is what I needed to hear! Great explanation of things. Thank you

 

[MagicMatt]

Also, if your dark grain is a significant part of your grain bill, you may want to factor in a little extra base malt to account for the missing (dark) grain if not mashing it for the full hour. Basically pull the dark grain from your recipe and then add enough extra malt to get back to your target OG.

You probably won't need much though, as you'll still get some conversion from the roasted malt over the ~20 minutes.

 

[bg1414]

Is it necessary to add baking soda or pickling lime to the kettle to get pH back up?

 

[MagicMatt]

Others may tell you differently, but once the mash is over I don't worry about pH (unless I'm doing a sour). There are two reasons I add baking soda (NaHCO3):

1) To the mash to raise the pH on really dark beers (i.e. adding it for the HCO3 content).
2) To the kettle to get my overall water profile in line with my target (i.e. adding it for the Na content)

Generally if I need Sodium added, I'd go to good ole table salt (NaCl) first. But if my Cl levels are already where I want them, I'll use baking soda in a pinch.