Stout Experiment – Brewing Details and Results

The recipe target the creation of 5 liters of 10 °P (1.040) wort, post boil.  I used a “brew in a bag” process, though unlike some I choose to mash with only a portion of the water and add the remainder as a sparge or rinse.  My default water to grain ratio is 3.0 liters per kilogram, which is somewhere around 1.5 quarts per pound.

Grains Amount Percent
Maris Otter 0.57 kg 68%
Flaked Barley 0.17 kg 20%
Roasted barley 0.10 kg 12%
Hops Amount Boil Time IBUs
Nugget  6 g 50 min 40

All batches were mashed at 68 °C for an hour.  My 4 gallon brew pot fits into my oven which is easier to control than using a propane burner.  It’s not perfect – my oven’s lowest setting is about 76° C – so I have to monitor the mash temperature with a remote probe and turn the oven off and on a few times during the one hour mash.  Still it was pretty worry free.

I made three separate “brew-in-a-bag” mashes.  The first batch was brewed in the normal manner, all grains mashed together.  The main mash of the next two batches consisted of only the base malt and the flaked barley.  For the second batch I added about 300 grams of water to the roasted barley and let it steep cold, overnight.  About a cup of liquid was drawn from this and added to the wort after mashing was complete.  For the third batch I  added the roast barley just prior to the end of the mash.  I did not write down exactly how long it was in the mash, maybe 3 to 5 minutes at most.

The first full mash achieved an extraction efficiency of 85%; the second two mashes were about 75%.  That is a pretty huge difference but until I can repeat the experiment I am not going to claim it as significant, merely interesting.  All three batches were 2.7 kg in the fermenter and pitched with 2.5 grams of Safale US05 dry yeast.  Thirty seconds of pure oxygen was also added after pitching.  Note I pitched the dry yeast directly on the wort.  While not really a best practice, I felt it would lend the best chance for consistency among the batches.

Interestingly all three batches ended at the same terminal gravity of 3.1 °P (1.012), so that the cold steep batch ended at a slightly lower ABV than the other two.

See Much Difference?

See Much Difference?

But the real question is:  how did they taste? And the simple answer is not much different at all.  The color of the foam on the fully mashed batch was ever so slightly darker than the other two, but the taste differences were simply nil.

My take away from this experiment is: do what works for you.  If your water is naturally high in alkalinity then a full mash with dark grains may be the simplest approach.  If your water is more balanced and you don’t want to fuss with mineral additions then by all means mash your pale grains first and let the starch conversion happen at the correct pH before adding your dark grains.  And if you are like me you can just make a quick water salt adjustment for the dark mashes.

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