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Topics - bcrowell

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General Homebrew Discussion / scientific paper on widgets, mouth feel
« on: March 04, 2011, 08:21:35 AM »

less technical summary here:

Here's the abstract:

"Bubble nucleation in stout beers
W. T. Lee, J. S. McKechnie, M. Devereux

    Abstract: Bubble nucleation in weakly supersaturated solutions of carbon dioxide - such as champagne, sparkling wines and carbonated beers - is well understood. Bubbles grow and detach from nucleation sites: gas pockets trapped within hollow cellulose fibres. This mechanism appears not to be active in stout beers that are supersaturated solutions of nitrogen and carbon dioxide. In their canned forms these beers require additional technology (widgets) to release the bubbles which will form the head of the beer. We extend the mathematical model of bubble nucleation in carbonated liquids to the case of two gasses and show that this nucleation mechanism is active in stout beers, though substantially slower than in carbonated beers and confirm this by observation. A rough calculation suggests that despite the slowness of the process, applying a coating of hollow porous fibres to the inside of a can or bottle could be a potential replacement for widgets."

I could steep my specialty grains while waiting for the water in the brewpot to come to a boil, then dump the liquid in with the water when it's ready, so it's present during the boil. On the other hand, I could wait until after the boil is over, or maybe add the liquid during the boil.

All other things being equal, it would be most convenient for me to do the specialty grains first, then let them cool while I'm doing my boil, and only add them to the main pot at the very end. This would help to give me a quick drop in temperature, which would be nice.

Is there any advantage to having the specialty-grain liquid in the wort earlier on? I suppose a higher boil volume would increase my hops utilization a little, although probably not by a huge amount. Are there fermentable sugars that will only be released if I boil the specialty-grain liquid for a while, or is it so poor in fermentable sugars that it doesn't matter? Does boiling the specialty-grain liquid affect the taste?

Extract/Partial Mash Brewing / controlling dryness
« on: July 03, 2010, 08:38:03 AM »
The recipe below is my current version of a Belgian strong dark ale I make. The first time I brewed it, I really liked the way it came out. It didn't come out very dry, and I thought the slightly sweet, malty flavor was excellent. That original recipe had only 1 lb of candi sugar, but 4 lb of amber dry extract. I had og=1.097, fg=1.032, which is 67% attenuation. I had a stuck fermentation, but was able to restart it.

For my second attempt, I wanted to avoid the stuck fermentation problem, so I increased the candi sugar and decreased the dry extract. I've brewed this new version of the recipe three times now, and usually get attenuation of more like 78-80%, no stuck fermentations.

What I really want is to have my cake and eat it too: I want slightly less than full attenuation, but I don't want hassles with stuck fermentation. Is there any way to accomplish what I'm trying to do? It seems like anything I do that reduces the fermentability of the wort will increase the chances of a stuck fermentation. Conceivably I could pasteurize it before it was done drying out, but I've never heard of a homebrewer doing that...?


2 lb Belgian candi sugar, amber or dark
8 lb light syrup
3 lb amber dry extract
1 lb Munich light
.25 lb Munich
.25 lb Special B
.5 lb Belgian caravienne
1 lb honey
17 AAU Cascade bittering
1/4 tsp yeast nutrient
WLP 500 Trappist Ale Yeast

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