GNBrews

Recipes 

I was reading about high gravity fermentation, and came across an article where the researchers used immobilized yeast. Basically it involves using the material that dentist use to cast dental impressions (sodium alginate) to encapsulate yeast into little jello-like spheres which are then put into the wort. The layer of alginate creates an environment around the yeast cell where there is a lower sugar concentration, which reduces osmotic stress. The alginate matrix does however impede new yeast growth, but this reduces diacetyl, and the cells remain viable longer than normal.

Have any of you guys messed with this technique or heard of it being used on the homebrew scale?

Here's a link to the article if any of you want to read it:
SpringerLink Home - Main

menschmaschine

Recipes 

Interesting article. I'd be surprised if anyone on here has tried this. Maybe Kaiser. But since yeast growth rate is reduced by 45% in this calcium alginate envelope, wouldn't you need double the yeast cell count to achieve proper levels for fermentation? Also, the article states that to compare flavor characteristics between encased yeast and regular yeast, they diluted 20-30°Plato beer to represent 12°Plato beer. How did they do that without changing the final gravity and hop bitterness/flavor between samples? (Plus they didn't find any significant flavor difference.)

The high level of FAN found in beer fermented with the alginate-yeast looks like it has positives and negatives and they talk about diacetyl reduction, but just do a diacytel rest and there won't be detectable amounts of diacetyl.

Overall, I'd say it's interesting, but probably more applicable to a commercial brewery who wants to make a high gravity specialty beer (like Sam Adams Utopias) with a yeast that normally couldn't handle it. For a homebrewer, it's probably not cost effective and with little return.

__________________
END TRANSMISSION