Base Malt Mash Water Chemistry for Imperial Stout

I’m going to be making an Imperial Stout soon, and I’ve been doing a 2 step mash, as per Gordon Strong’s suggestion, just the base malts for most of the time (~40 min.), and then add the dark malts for the last 15 min. or so.  I’m convinced this helps the dark malt flavors, thanks, Gordon.

I recently tested my water, and am using John Palmer’s spread sheet for residual alkalinity and additions calculations.  So my 1st mash is basically the same as for a light colored IPA, little acid added with those malts, but then I want the water to be right for the final beer, which would become much more acidic after the dark malts are added.  Suggestions?  Thanks,

You’re holding off with the dark grains, but that means you need to acidify? I would acidify with the dark grains. In other words, I would not bother with Gordons suggestion. Or not worry about the spreadsheet.

Dave, do you really need to hold off on the dark malts?  I’ve found that with the correct water adjustment I can add them right to the mash and get the same result with less hassle.  Also, with all due respect to John, I find Martin’s spreadsheet much more accurate especially for dark beers.

Jim,

Just doing a single infusion with the right water for the stout is probably my best bet, but I think I get better flavors with the 2 step, and that’s just with my somewhat minerally town water.  I need to do the spread sheet for the stout, and I’ll bet my water needs very little adjustment.  Thanks,

Denny, I started looking into Martin’s method, met him at the last NHC, really nice guy, and you’re among many who like his results.  Sounds like the 2 stage may not be the way to go.  Thanks,

I honestly think that if you get your water adjustments right in the first place and hit the right pH (I like the 5.5-5.6 range for stouts and porters), then adding your roasted grains late isn’t going to gain you any advantage. The only exception is possibly a dry stout, since the target pH is a bit lower.

I completely agree.  The method is a work around for not adjust9ng your water correctly.  Ooops, don’t tell Gordon I said that!  :slight_smile:

If you add your dark malts to the mash at the same time as the base malts, you will likely have to add an alkaline salt in which case you can move some of the dark malts to the end of the mash so that you don’t have to make large mash adjustments.  I have not seen very conclusive information on what the desired pH of the pre-boil wort should be for a stout vs beers generally.  There tends to be less astringency from adding dark malts later in the mash or in doing cold extracts.

In my personal experience I’ve seen a big improvement in my dark beers when I went from mashing in the 5.3-5.4 range up to 5.6 - the roast flavor seems to pop more without being harsh.

To my palate, low pH on a stout/porter is very similar to an IPA that is too acidic. The bitterness and flavors become too muddled. In the case of the dark beers it’s the bite of the roasted grains that gets washed out, as opposed to the hops. But that’s my palate - I like my stouts to have a solid roasty bite.

for me the jury is still out on the late add to mash technique. the beer I did this way is crashing now and will keg tonight. I was trying it in comparison to cold steep though. tasting the wort and the gravity samples I did taste a difference between this method and cold steeping. Slightly more harsh roastiness with the addition to the mash rather than cold steep.

+2.  I’m making my best dark beers ever by mashing all the grain together, adjusting pH up to 5.5 with baking soda ( using RO).

Gordon’s method (it’s actually Guinness’ method) is ONLY suited when brewing with very low alkalinity water like distilled or RO water. Under that condition, if the dark malts were added to the main mash, the mash pH would be too low and there would be issues with both the acidity of the wort and the conversion of starch. When you use the Guinness method, you avoid problems with starch conversion…but you still end up with a potentially too acidic wort. Extra acidity is OK in dry stouts, but it’s not OK in other stout and porter styles. Interestingly, one of the World Beer Cup gold medal winning beers was brewed in an Ohio city a few hours from Gordon’s home. That brewer is blessed?? with typical hard and alkaline Midwestern water that happens to make fantastic dark beers.  They could not have done it with the Guinness method.

I get a chuckle out of brewers that state that this method reduces the edge of their roast malt flavors. The real reason that the roast flavors are reduced is that the overly low pH reduces the extraction of color and flavor from those dark grains. I suggest that those of you that want to reduce the roasty flavor in your dark beers might try reducing the quantity of those roasted grains in the recipe…it’s cheaper that way.

As you can tell by now, I’m not impressed by this method. Brewers do make better dark beers when they understand and manipulate the alkalinity of their mashing water. I find that there are only a few beer styles that actually benefit from this technique. Irish dry stout and Schwartzbier are examples.

In the case of an Imperial Stout, using mashing water with the proper alkalinity level is more likely to produce pleasant and full roast flavors instead of the dry and potentially acrid roast flavors that accompany overly low wort pH.

Enjoy!

Thanks for this explanation, Martin. This is the first time I’ve heard someone describe this in a way that matches my experience. Bumping up my alkalinity to target a higher pH on porters & stouts has really helped me achieve the fullness of roast flavors that I was chasing.

How low of of pH is too low?  Is it an extremely narrow window?

To add another question. If using RO water, what would you suggest adding to get the alkalinity and ph into the proper range?

Pickling lime or baking soda would be good choices, depending on how much alkalinity you need to add and your preference for sodium levels.

[quote]How low of of pH is too low?  Is it an extremely narrow window?
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Like many brewers here, I like a target of 5.5-5.6 for dark roasty porters or stouts. I would not want to fall much below 5.4 and would consider that too low. I also use RO water, and some baking soda to raise the alkalinity enough to fall close to 5.6. The little sodium that adds seems beneficial to the roast character.

Like many brewers here, I like a target of 5.5-5.6 for dark roasty porters or stouts. I would not want to fall much below 5.4 and would consider that too low. I also use RO water, and some baking soda to raise the alkalinity enough to fall close to 5.6. The little sodium that adds seems beneficial to the roast character.

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I don’t use RO per se, but I have a very soft well, and I do the same thing. Any base water that is low in sodium is well suited for using baking soda to raise alkalinity. I do like a small amount of sodium in my malt-forward beers.

Ok, understood.  Thanks!

Like many brewers here, I like a target of 5.5-5.6 for dark roasty porters or stouts. I would not want to fall much below 5.4 and would consider that too low. I also use RO water, and some baking soda to raise the alkalinity enough to fall close to 5.6. The little sodium that adds seems beneficial to the roast character.

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+1

Those that read the article on London water a few months ago, saw that the water in central London had a somewhat high sodium content through some its history. The porter breweries were reputed to make the most tasty beers for the style, even when compared to other porters from around the world. Having brewed that brown porter recipe that I created for the article and having brewed it with the ‘London Porter’ water profile, I can attest that the 110 ppm sodium content is not detrimental to the beer. If anything, I would say that you would want at least 50 ppm sodium in a porter to help round the flavor. For that reason, using baking soda is well suited to dark beer brewing.

Another consideration is that since you only add baking soda to the mashing water, the high sodium content that might be shown from the baking soda addition will be diluted when you add the sparging water. In the free version of Bru’n Water, you would have to perform that calculation by yourself. But in the supporter’s version, the diluted ion concentrations that are produced in the kettle are shown automatically.