Mashing the Perfect Sweet Stout

Hop · 04-15-2010, 05:42 PM

Note: Also available over at Mad Alchemist

Creating the perfect water profile and mash for a sweet stout is an exercise in contradiction. You want the beer to be very dark, sweet, malty, and full-bodied. It should have some roasted and toasty notes without astringency. To me, that translates to the following information concerning the mash and water profile: Keep the pH of the mash fairly high, around 5.6 (at room temperature). Keep the Chloride to Sulfate ratio high, around 3 to 1. Ensure Chloride and Sodium are both above 100, but below 150. Keep the temperature of the mash up around 158°F. It also means a thicker mash of around 1.25 quarts of water per pound of grain.

Where does the contradiction come in? Mostly with the grain bill. You're looking at 10-15% of your grist being dark, roasted malt, which will drive the pH of the mash down significantly. It's quite difficult to get a pH of more than 5.2-5.3 (at room temperature) without ending up with too much of something in the final beer (like sodium or bicarbonates). The reason I want to keep the pH up in the 5.4-5.6 range is because I use diastatically weak base malts for sweet stouts (like Munich or Maris Otter), and it's better for enzymatic activity in that range. It's also theoretically going to favor alpha amylase in this higher range, while beta amylase is favored a bit lower. Favoring alpha amylase is the same reason I keep the mash temperature up high at around 158°F.

The higher the Chloride to Sulfate ratio, the more malty the final beer is going to be. You need about 100ppm of Chloride before it has significant impact, and the same generally goes for Sodium (which rounds out the beer at that level, and I find that desirable in a sweet stout). You also, of course, need at least 50ppm of Calcium. The problem with the Calcium is that it lowers pH, but you really don't want too much Bicarbonate in beer (some people believe it creates undesirable flavors, even though a lot of it will precipitate out, so I err on the side of caution here).

Okay, I think that's enough of the reasoning behind the numbers I aim for with a sweet stout. On to the solution(s).

The first solution I came up with was to only worry about pH during the mash, and add all of the other minerals to the water after the mash. So, I'd add Sodium Bicarbonate and/or Calcium Carbonate during the mash to raise pH, then Calcium Chloride and Magnesium (or Calcium) Sulfate after the mash. Truthfully, this seemed to work out pretty well (and A.J. deLange corroborated), but I believe there is a better, and easier, way.

Don't mash your roasted grains. Roasted grains will drive the pH down considerably, so it's difficult to keep the pH high no matter what fancy solution you use during the mash. Roasted grains have the wonderful benefit of not needing to be mashed. So, the best solution, in my opinion, is to mash everything except for your roasted grains in your MLT, and steep your roasted grains in a separate vessel simultaneously. Then, combine the wort created by the roasted grains with the mashed wort in the brew kettle.

I would not recommend sparging with the roasted wort, in part because you're going to impact the sparge pH pretty significantly, and in part because you're somewhat defeating the purpose of rinsing all the sugars out of the grist by adding more in their place.

Hitting the ideal concentrations of all ions in the brewing water as well as the ideal pH is very easy when you leave out your roasted malts (and any other malts that don't need to be mashed, such as caramel/crystal). By steeping the roasted malts (and, optionally, your crystal malts) separate from the mash, you might end up with a much better sweet stout in the end.

**uwjester** · 04-15-2010, 06:02 PM

Very nice write-up. I'm doing a sweet stout in a few weeks, so I'm very interested in your gravities turn out. I have some other additions that I don't want in the boil, tea leaves and lactose. What do you think about steeping those with the roasted grains and then adding the whole solution to the boil kettle shortly after flameout? I assume it will affect hop utilization so I have to add a little extra. Any other considerations?

Hop · 04-15-2010, 06:45 PM

Tea leaves would be good to put into the steep. Lactose would be added during the boil in either case (you still want to boil what you steep, just not mash it), so you'll have to account for its gravity during the boil...

Unless, you add it when bottling. I usually add my lactose with my priming sugar before I bottle. All you really need to do is sanitize it, just like the priming sugar, so it's safe to do during bottling instead of in the boil. I do that for the same reason you mentioned (hops utilization).

You can also add it right near the end of the boil to minimally impact hops utilization, sanitize the lactose, and get the clumps broken up by a brief boil.

Hop · 04-17-2010, 05:06 AM

I should have also elaborated a bit on when to combine the wort from the steeped roasted grains with the mashed wort: Do it at the beginning of the boil. There are a number of reasons to do this, such as:

Maillard reactions/melanoidins
To sanitize the wort
To drive off unwanted volatiles
To coagulate unwanted proteins (hot break)

**Schnitzengiggle** · 04-17-2010, 05:31 AM

Awesome suggestions, my first two sweet souts were extract plus steeping grain recipes, and they were great. My first attempt at an AG sweet sout, not so great, beer is black as outer space, very full bodied (which is good), but came out quite bitter, and finished extremely high.

I mashed all my grains, I did not use any 5.2, the beer is okay, but disappointing.

Thank you for the input Sweet Stout is one of my favorite beers, and I think your data will be extremem,oy beneficial.

Cheers!

Hop · 04-20-2010, 05:57 PM

You're welcome. Yeah, the bitterness is the issue I tend to have problems addressing in sweet stout. It's easier for me to build the water for a sulfate-heavy dark beer than a chloride-heavy dark beer. Magnesium Sulfate is an easy way to get a lot of Sulfate without dropping Residual Alkalinity, as opposed to Calcium Chloride or Sodium Chloride, the latter of which could cause problems with too much sodium.

Sweet stouts should be chloride heavy, and the chloride needs to be above 100 ppm to break the taste threshold (I believe that data is according to Brew Strong, How to Brew, or Designing Great Beers... I've read and listened to so much I confuse the origin of my data).

You also need a decent amount of sodium to round the character and accentuate sweetness, but don't want to break 150 ppm of sodium or you can start getting into undesirable flavors such as saltiness or sharp bitterness (which theoretically really hits around 200 ppm Na).

So, all things considered, it's much simpler to steep your roasted grains for a sweet stout than to include them in the mash. Another thing this does that I see as a benefit is that steeping won't extract any fermentables from the roasted grains (if there are any) because you have no enzymes present for conversion. While this might contribute cloudiness to a lighter beer, it will contribute additional body to the finished beer and you really shouldn't notice haze in a beer that is 30+ SRM.

**KevinW** · 04-20-2010, 06:46 PM

Please forgive my ignorance here but I was under the impression that the chemistry of the water was only important during the mash!
If I am correct in what you are saying is that mineral adjustments to water post-mash can effect flavor as well?
I am intrigued by the idea of steeping the roasted grains though and I am looking forward to trying it out!
Great post!

Hop · 04-20-2010, 09:29 PM

The chemistry of the water is important during the mash for pH and proper conversion. However, the concentrations of ions within the water impact the overall flavor of the beer no matter when they are added (you could even add them at bottling if you are weird).

I concern myself primarily with proper conversion during the mash, then with the overall balance of chloride and sulfate before the boil (as well as ensuring at least 50 ppm of calcium for yeast happiness).

**KevinW** · 04-21-2010, 09:30 PM

Quote:

Originally Posted by Hop

The chemistry of the water is important during the mash for pH and proper conversion. However, the concentrations of ions within the water impact the overall flavor of the beer no matter when they are added (you could even add them at bottling if you are weird).

I concern myself primarily with proper conversion during the mash, then with the overall balance of chloride and sulfate before the boil (as well as ensuring at least 50 ppm of calcium for yeast happiness).

I see what you mean, thanks!

To make sure I understand, would you mash your base grain at say a similar profile to Pilsn(or would Burton be better)? Then add the steeped wort from the specialty grains for the boil?

I am in Portland, OR and we have water that is virtually identical to Pilsn so that would be easy!