Adding roasted/dark grains late in mash: what water chemistry?

[Ike]

SO, I tend to be a run-of-the-mill ales and IPAs kind of guy. I've brewed two stouts so far, both of which seem to have turned out OK. For the record, I do full boil sized BIAB.

BUT, I'm kicking it up a notch and trying to brew marubozos RIS (HBT 2011 award winner). This is a much bigger stout than I've ever done. As others also have, I'm struggling a bit with water chemistry. Usually, I start with distilled water from the store, then build the water up using Brewer's Friend's water caculator as a guide. In order to meet BF's "stout" profile, I need to use a fair amount of salts, including a rather hefty 13g of chalk. After/In addition to that, I'm having to add 2% acid malt AND 60ml 10% Phosphoric to get the mash pH where I want it.

Enter the idea of adding roasted/dark malts late in the mash. AHA! Apparently, my pH problems are solved!

BUT: here's the question. Do I still add all those salts to the full mash?

1.) OR, do I use salts more typical for the fermenting of 17 pounds of 2-row, which is basically what this is without all the dark grains, and just skip the rest?

OR

2.) Do I salt for the paler brew as above for the mash, then add the remainder of the salts with the darker grains (i.e. 10-15 mins before end of mash)?


As you can imagine, just mashing the 2-row with the "stout" salt additions makes the pH target even HARDER to hit, so I don't think that's the answer. BUT, I've been wrong before...

Thanks;

Ike


P.S. recipe thread here: https://www.homebrewtalk.com/showthread.php?t=238807

 

[jtratcliff]

I'm not an experienced water chemistry guy, so take this with a grain of *salt* haha...
But I think the mineral profile for a "stout" is for more than just the mash... Your pH adjustments (and late grain additions) are mostly for the mash pH but the rest is for mash plus finished product.

Without any *real* knowledge of the subject, I'd keep your mineral additions mostly the same but adjust for pH variation of late roasted grain additions.

Hopefully someone knowledgeable will chime in... To tell me if how wrong I am...

 

[Sadu]

There's 2 things you are trying to achieve here.

Firstly is mash pH. You want it to be within a certain range for reasons you probably know..

If you are doing late additions of the dark grains then I would adjust your mash pH as if the dark grains weren't there since you are effectively mashing a pale beer. For example when I brew a schwarzbier I treat it like a pilsner, including 3% acidulated malt to bring the pH down into the right range. I don't stress about the pH dropping when I add the dark stuff at the end, since the pH has been good for the first 80 mins of the mash which is where all the action happens.

As a side note, I do late additions on the schwarzbier to get color but avoid too much roast flavor. For a stout you want that roast flavor, surely? Is there another way to do what you are trying to achieve?

Second thing you are trying to do is to adjust the amounts of salts in the finished beer as some of these affect flavor. I find I can do everything I want with Calcium Chloride / Calcium Sulfate. These slightly acidify your mash so this is the driving factor for me when to add them. For dark beers you don't want to lower the mash pH so don't add these to the mash.

If this was me, with my relatively soft water...
- Mash all grains together
- Use Baking soda in the mash to bring up the mash pH, so long as the Sodium in the finished beer stays below 50-75ppm
- Add Calcium Chloride and Calcium Sulfate (Gypsum) to the boil kettle to give 50-100ppm Calcium and whatever target you want for Chloride and Sulfate. Don't add these to the mash as they will work against you with regards to mash pH.

 

[mabrungard]

NO! Your pH problems are not necessarily solved by reserving your roast grains until the end of the mash. That technique can help produce an appropriate mash pH early in the process, but the pH of the kettle wort and the subsequent beer will be low. That result can be OK in beers such as Irish Dry Stout, Munich Dunkel, and Schwartbier where you either want it to be acidic (dry stout) or the amount of roast is small and the pH drop is minor (dunkel, schwartz). In typical stouts and porters, the result can be overwhelmingly poor. The amount of roasted grains is likely to drive your kettle wort pH way too low. Keeping your kettle wort pH in the 5.4 to 5.6 range has proven to be beneficial for flavor of typical stouts and porters.

Forget about chalk since it cannot dissolve in the mash or kettle due to most of the acids in wort being "weak". The chalk will just settle to the bottom of your tun or kettle and not increase the wort pH as intended. Pickling lime and baking soda are much more effective for increasing the alkalinity of water used to mash roasty beers. Don't be afraid of the sodium contributions of baking soda since sodium has been proven to be beneficial to beer flavor and the minor amount used in the mash will not boost the sodium concentration in the beer that much.

 

[Ike]

@mabrungard: I've also been reading up on RIS water chemistry threads here on HBT. In those threads (and this one) you seem to indicate that the bicarbonate is contributing to alkalinity, but that alkalinity isn't the end point: the final pH of the mash and brew pH is.

If that's the case, I may have a situation where I'm creating more alkalinity than I need. Again, I'm using Brewer's Friend and the HCO targets for the Dry Stout and "London" (dark ales and porters) have HCO targets of 280 and 265, respectively. The end result is a very high pH (even with all the dark malts I'm using) and a pretty heavy acid need (2% acid malt and 60ml of 10% phosphoric).

If I don't NEED that alkalinity, can I reduce it in order to also reduce my acid burden? Doing so makes me feel much better about the situation... I think.

Thanks!

 

[makubex]

NO! Your pH problems are not necessarily solved by reserving your roast grains until the end of the mash. That technique can help produce an appropriate mash pH early in the process, but the pH of the kettle wort and the subsequent beer will be low. That result can be OK in beers such as Irish Dry Stout, Munich Dunkel, and Schwartbier where you either want it to be acidic (dry stout) or the amount of roast is small and the pH drop is minor (dunkel, schwartz). In typical stouts and porters, the result can be overwhelmingly poor. The amount of roasted grains is likely to drive your kettle wort pH way too low. Keeping your kettle wort pH in the 5.4 to 5.6 range has proven to be beneficial for flavor of typical stouts and porters.

Forget about chalk since it cannot dissolve in the mash or kettle due to most of the acids in wort being "weak". The chalk will just settle to the bottom of your tun or kettle and not increase the wort pH as intended. Pickling lime and baking soda are much more effective for increasing the alkalinity of water used to mash roasty beers. Don't be afraid of the sodium contributions of baking soda since sodium has been proven to be beneficial to beer flavor and the minor amount used in the mash will not boost the sodium concentration in the beer that much.

Hi Martin, huge fan. Long time listener, first time caller.

I was hoping you could critique my technique that I've been using for dark beers. I'm a subscriber to the school of adding roast grains at the end of a mash, as to reduce the amounc of acridity/astringency contributed by those grains. As such, I've been doing my mineral additions in two steps.

First, I use bru'n water to calculate the mineral addition necessary to bring my mash pH to 5.3-5.4 without the roasted grains. I create a separate bru'n water spreadsheet and calculate what my mineral additions should be with the roasted grains incorporated.

When I begin my mash, I add all of my non-roasted grains, my RO water, and all of the minerals calculated from the first (non-roasted) spreadsheet to the mash tun. When there is 15 minutes remaining in my mash cycle, I then add the roasted grains, and the additional minerals calculated in the second spreadsheet.

Do you see any obvious flaws with this approach? Thanks in advance!

 

[xpops]

Hi Martin, huge fan. Long time listener, first time caller.

I was hoping you could critique my technique that I've been using for dark beers. I'm a subscriber to the school of adding roast grains at the end of a mash, as to reduce the amounc of acridity/astringency contributed by those grains. As such, I've been doing my mineral additions in two steps.

First, I use bru'n water to calculate the mineral addition necessary to bring my mash pH to 5.3-5.4 without the roasted grains. I create a separate bru'n water spreadsheet and calculate what my mineral additions should be with the roasted grains incorporated.

When I begin my mash, I add all of my non-roasted grains, my RO water, and all of the minerals calculated from the first (non-roasted) spreadsheet to the mash tun. When there is 15 minutes remaining in my mash cycle, I then add the roasted grains, and the additional minerals calculated in the second spreadsheet.

Do you see any obvious flaws with this approach? Thanks in advance!

I've been considering doing the same thing for a schwarzbier i'm brewing this weekend - would love to hear some input from the Expert!

 

[mabrungard]

When I begin my mash, I add all of my non-roasted grains, my RO water, and all of the minerals calculated from the first (non-roasted) spreadsheet to the mash tun. When there is 15 minutes remaining in my mash cycle, I then add the roasted grains, and the additional minerals calculated in the second spreadsheet.

So you are adding alkalinity at the end of the mash to avoid a pH drop with the roast addition? If the roast addition is large and the pH drop is significant, then it would be wise to add the extra alkalinity. But if the beer is something like a Schwartzbier or Black IPA and you are only adding a bit of roast for its color, then pH is probably not shifting much and there is little need to add alkalinity to counter that drop.

In the case of grists with large roast addition and you know the pH will drop significantly, I don't find that the 'reserve the roast' technique is very useful. Having the proper mashing water alkalinity at the start of mashing that keeps the pH in the proper range when the roast is added at the beginning of the mash works better in my opinion. I don't find there is an advantage or improvement in roast flavor from using that delayed roast technique. (Dry Stout brewing is the exception to that finding!)

 

[xpops]

So you are adding alkalinity at the end of the mash to avoid a pH drop with the roast addition? If the roast addition is large and the pH drop is significant, then it would be wise to add the extra alkalinity. But if the beer is something like a Schwartzbier or Black IPA and you are only adding a bit of roast for its color, then pH is probably not shifting much and there is little need to add alkalinity to counter that drop.

In the case of grists with large roast addition and you know the pH will drop significantly, I don't find that the 'reserve the roast' technique is very useful. Having the proper mashing water alkalinity at the start of mashing that keeps the pH in the proper range when the roast is added at the beginning of the mash works better in my opinion. I don't find there is an advantage or improvement in roast flavor from using that delayed roast technique. (Dry Stout brewing is the exception to that finding!)

Thanks Martin - that definitely helps me sort out adding 1% grist of Carafa at the end of mash for a Schwarzbier. hopefully it helps out the OP as well!

 

[cahernandezgalaviz]

So you are adding alkalinity at the end of the mash to avoid a pH drop with the roast addition? If the roast addition is large and the pH drop is significant, then it would be wise to add the extra alkalinity. But if the beer is something like a Schwartzbier or Black IPA and you are only adding a bit of roast for its color, then pH is probably not shifting much and there is little need to add alkalinity to counter that drop.

In the case of grists with large roast addition and you know the pH will drop significantly, I don't find that the 'reserve the roast' technique is very useful. Having the proper mashing water alkalinity at the start of mashing that keeps the pH in the proper range when the roast is added at the beginning of the mash works better in my opinion. I don't find there is an advantage or improvement in roast flavor from using that delayed roast technique. (Dry Stout brewing is the exception to that finding!)

Hey Martin, thanks for the excellent Brun Water! Question for you: what would you consider a large roast addition? I have a Porter with a 9% addition of black and chocolate malt (4.5% each addition), and I was adding the grains late in the mash (your thoughts on this are convincing me to add these grains at the beginning of the mash).

I'm also going to brew a Schwartzbier and it has a 8% Carafa II Special addition and I was thinking about adding the grains at the end, but I suspect that 8% is a significant addition, and pH will drop significantly if I add them at the end of the mash, giving me unwanted acidity...

 

[mabrungard]

Hey Martin, thanks for the excellent Brun Water! Question for you: what would you consider a large roast addition? I have a Porter with a 9% addition of black and chocolate malt (4.5% each addition), and I was adding the grains late in the mash (your thoughts on this are convincing me to add these grains at the beginning of the mash).

I'm also going to brew a Schwartzbier and it has a 8% Carafa II Special addition and I was thinking about adding the grains at the end, but I suspect that 8% is a significant addition, and pH will drop significantly if I add them at the end of the mash, giving me unwanted acidity...

Those are large additions. I sometimes employ dark roast to impart a bit of color without much roast flavor. Those additions are typically less than 2% and they don't depress pH much. I am concerned with your 8% carafa addition in a Schwartzbier since that is going to impart a significant roast note that I don't believe should exhibit in that style, low to moderate is desirable. It shouldn't take that much to get the color you want.

Having some acidity in the wort (exhibited as a slightly low pH, say around 5.2) can be OK. But if the roast addition is going to drive the wort pH lower, that can have detrimental effect since proteolysis is increased at lower pH and that can leave you with a thinner body and mouthfeel. An important fact for brewing an Irish Dry Stout (which is typically a notably acidic beer), is that they perform a mash with the barley and pale malt at a typical mashing pH and then add the roast (or the liquor from a roast steep) to the overall wort after the mash to bring the kettle or fermenter wort pH down. The point is that you want to avoid an overly low mashing pH at all costs.