highgravitybacon
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So the research differs greatly from practice. The research on flocculation finds that flocculation is increased by agitation, not reduced by it. Which makes sense, because if the yeast flocculation is a consequence of chemical bonds between two yeast cells, anything that increases the chances of yeast bumping into other yeast would then increase the flocculation. Then as clumps get bigger, they fall faster.
This differs from the usual practice of swirling the carboy to rouse the yeast. It would seems that trying to rouse yeast may be counter productive. However, the yeast can deflocculate in the presence of sugars so the swirling would then expose the cells to sugar to encourage further fermentation.
One text I read last night said that gentle swirling of 70-120 rpm maybe even using CO2 to bubble it would hasten flocculation.
It's not a causal thing, but I did notice a dramatic change in some carboys I shuttled around the house. For weeks, I'd been waiting for a beer to clear. It was a poorly flocculant yeast. For the longest time, I always treated these clearing carboys like fine china. Super gentle, don't want to disturb the yeast, etc.. But I wasn't very kind with these last two batches. Treated them like a rented mule.
Within days, they were rapidly clearing. It was after the fact that I did this bit of reading about flocculation so pick your logical fallacy and insert [here]. But I like the theory.
Has anyone else noticed this or played around with the idea that gentle agitation works to increase flocculation and thus clearing?
Here's a snippet from the undisputed source of all facts, Wikipedia:
For flocculation to occur the yeast must be flocculent and the environmental conditions (such as agitation, absence of sugars, a microamount of Ca2+, ethanol, etc.; Jin and Speers 1999). Several factors are important in cell-to-cell binding such as surface charge, hydrophobic effects and zymolectin interactions (see following). The importance of these forces in brewing yeast flocculation was unrecognized but work by Speers et al. (2006)[1] have indicated the importance of zymolectin and hydrophobic interactions. As the cells are too large to be moved by Brownian motion, for binding of two or more cells to occur the cells must subjected to low level of agitation.
This differs from the usual practice of swirling the carboy to rouse the yeast. It would seems that trying to rouse yeast may be counter productive. However, the yeast can deflocculate in the presence of sugars so the swirling would then expose the cells to sugar to encourage further fermentation.
One text I read last night said that gentle swirling of 70-120 rpm maybe even using CO2 to bubble it would hasten flocculation.
It's not a causal thing, but I did notice a dramatic change in some carboys I shuttled around the house. For weeks, I'd been waiting for a beer to clear. It was a poorly flocculant yeast. For the longest time, I always treated these clearing carboys like fine china. Super gentle, don't want to disturb the yeast, etc.. But I wasn't very kind with these last two batches. Treated them like a rented mule.
Within days, they were rapidly clearing. It was after the fact that I did this bit of reading about flocculation so pick your logical fallacy and insert [here]. But I like the theory.
Has anyone else noticed this or played around with the idea that gentle agitation works to increase flocculation and thus clearing?
Here's a snippet from the undisputed source of all facts, Wikipedia:
For flocculation to occur the yeast must be flocculent and the environmental conditions (such as agitation, absence of sugars, a microamount of Ca2+, ethanol, etc.; Jin and Speers 1999). Several factors are important in cell-to-cell binding such as surface charge, hydrophobic effects and zymolectin interactions (see following). The importance of these forces in brewing yeast flocculation was unrecognized but work by Speers et al. (2006)[1] have indicated the importance of zymolectin and hydrophobic interactions. As the cells are too large to be moved by Brownian motion, for binding of two or more cells to occur the cells must subjected to low level of agitation.