Russian Imperial Stout Water Chemistry

[rlonardo]

In the coming weeks I'm planning to brew the Russian Imperial Stout which appeared in October's BYO. It will be my first attempt at water chemistry and I would appreciate any tips/suggestions you may have! I would also appreciate if anyone could share a good water chemistry calculator with me.

For your reference, the recipe is below. I am also planning to use distilled water for this brew.

Grains:
13 lb. Maris otter
3 lb. 6.4 oz. Munich
1 lb. 1.6 oz. white wheat
9 oz Carafa III
9 oz. chocolate malt
9 oz. roasted barley
9 oz. special B
2 lb. 6.4 oz DME

Hops:
1.8 oz. galena @ 60 min
1.5 oz simcoe @ 10 min

This is a 5 gallon recipe. Mash in with 26 qts at 154 F.

 

[ajdelange]

My advice is always to start out simple. To your 6.5 gal of mash water add about 3/4 tsp of calcium chloride. That's all you really need to do but one question is clearly left unanswered and that is 'what about sulfate?' If you know, from your other beers, that you like the effects of sulfate then use half gypsum and half calcium chloride. In either case after the beer is brewed experiment with adding additional amounts of gypsum and/or calcium chloride in the glass to find out where your sulfate sweet spot is.

Dark beers are always a bit tricky because of the acidity of the dark malt and you have no alkalinity to absorb any extra acid. Indications are that you will probably be OK and will probably have a mash pH close to 5.4. You are reasonably secure here because you have a relatively large amount of base malt to absorb any extra acid. Making certain assumptions about how your malts resemble the malts that I and Kai Troester have measured in the past I calculate a pH of 5.39. If the special B turns out to be twice as acidic as I have assumed then that estimate drops to 5.36 - the rest of the malts are buffering for you. I have assumed that your base malt has a DI mash pH of 5.62. I have not measured MO but it is reported to have a DI mash pH that low. Should the malt you actually use have a higher DI mash pH, e.g. 5.72 then that will pull your mash pH higher to 5.45. Still not bad at all. Nonetheless, especially in doing dark beers, it is always best to use a pH meter to find the pH of a test mash because of the uncertainties in the properties of the relatively large proportions of high colored malts used.

As for calculators: they abound. I'd say to get copies of several and compare them. Use the one you are comfortable with. Comfort usually means that you can use the thing with facility and that it give acceptably good pH predictions for the kinds of beer you brew. In order to know whether it does or not, of course, you will have to obtain a pH meter and compare predictions to actual measurements. If you are going to be a serious brewer a pH meter is in your future.

 

[mabrungard]

I recommend a modest level of mineralization in a beer like RIS. That water should be firmly in the background and not a player in the flavors.

I do disagree with avoiding any sulfate content in the water. Sulfate is an important component in producing a drying finish in the beer. However, since RIS is a somewhat roasty style, I caution against adding too much sulfate. 100 ppm sulfate may be too much for some tastes, but I do suggest that at least 50 ppm sulfate be included. As another data point, Burton on Trent was once a major producer of big malty ales such as RIS and Burton Ale. As most know, Burton water has high sulfate content (often 300 ppm or more). That level of sulfate does help dry those big beers out to keep them from being cloying.