Yeast Washing Exposed

This is a post directed at Woodland Brewing Blog... Having trouble posting comments from my iPad. In your Yeast Washing Exposed post you talk about the viability and bacteria content of the layers in a washed yeast jar. Basically you say that the viability of yeast throughout the sediment is equal and that the cell count is pretty high in what people assume is the trub layer. You also say that bacteria levels are the highest in the water layer. You recommend decanting just the water layer, keeping all of the sediment, and adding sanitized water. Would you recommend doing this with older, stored jars? Or would the contamination risk out weigh the benefit? Others can feel free to add their thoughts. Great blog by the way.

Here is the original post:
http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html

And this is a more recent post revisiting the issue:
http://woodlandbrew.blogspot.com/2013/01/yeast-washing-revisited.html

tagz said:

This is a post directed at Woodland Brewing Blog... Having trouble posting comments from my iPad. In your Yeast Washing Exposed post you talk about the viability and bacteria content of the layers in a washed yeast jar. Basically you say that the viability of yeast throughout the sediment is equal and that the cell count is pretty high in what people assume is the true layer. You also say that bacteria levels are the highest in the water layer. You recommend decanting just the water layer, keeping all of the sediment, and adding sanitized water. Would you recommend doing this with older, stored jars? Or would the contamination risk out weigh the benefit? Others can feel free to add their thoughts. Great blog by the way.

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Thanks!

What you wrote is a good summary of what I have seen.

There are some benefits to storing in beer compared to water such as lower pH, and higher alcohol. So it really depends on how clean the stored slurry is. For most people I would wager a guess that it would be beneficial to decant and replace with water. The only place I have seen extremely low bacteria counts is in tap water and professionally packaged yeast. Even high quality beer can have an alarming amount of bacteria in the yeast slurry at the bottom of a bottle. Bacteria has a way of work of it's way into beer regardless of how careful you might be. It's keeping that bacteria minimized that is crucial to making great beer.

Does trub have any impact on future performance or long term storage? I just washed some 1968 and foused my energy decanting the liquid layer rather than separating the trub. As a result I have a much larger quantity of solids (and presumably yeast) than I normally do. It is much less clean though. Is there any drawback to letting yeast sit mixed with trub over the long term?

tagz said:

Does trub have any impact on future performance or long term storage? I just washed some 1968 and foused my energy decanting the liquid layer rather than separating the trub. As a result I have a much larger quantity of solids (and presumably yeast) than I normally do. It is much less clean though. Is there any drawback to letting yeast sit mixed with trub over the long term?

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not that i've noticed. most breweries that pull yeast out of the cone for repitching do not wash it at all, just dump it in.

Great blog, very educational.