Why don't we agitate during fermentation?

[machinelf]

Hey corncob, how'd your beer turn out? I'm working on a SS Pale Ale right now... curious as to how you liked the Yorkshire yeast...

Maybe I am naive about what I read on the internet, but I have been trying to brew something remotely close to Samuel Smith's Organic Pale Ale since I first started brewing. I read this:

http://www.merchantduvin.com/pages/5_breweries/samsmith_yorkshire.html

I bought four vials of WLP037 Yorkshire Square Ale Yeast. I have a batch of 1.045 bitter w/ fuggles and goldings in the closet at 65*.

And I've been swirling it something awful twice a day since the bubbles started. I'll let you all know in a few weeks. Ahhhhhh science!

 

[JimmyT555]

I have heard agitation is good as long as you have an airlock or blow off tube on your fermenter. By agitiating the yeast you are in a sense creating a larger surface area for the yeast to absorb nutrients from the wort. As long as oxygen is not being introduced agitiation is good. It can also help speed up the primary fermentation time.

 

[lamarguy]

I have heard agitation is good as long as you have an airlock or blow off tube on your fermenter.

Agitation is certainly beneficial for decreasing fermentation time.

The jury is still out on potential flavor regressions (e.g., increased esters, fusels) compared to a non-stirred fermentation.

 

[ae4853t]

The original large scale stir bar idea was discussed here.

I plan to use a closed, positive pressure vessel to conduct the fermentation test. I'll likely split a 5.5 gallon batch and ferment at the same temperature.

Yes, the size of the stir bar and centrifugal force is certainly a design concern. The goal is to achieve minimal agitation at the bottom of the fermenter, not a vigorous whirlpool. I believe that can be achieved with a 3" - 4" stir bar and a large 6" computer fan.

Only real world testing will tell. Once I get my repaired sanke fermentation kit back next week, I should have an opportunity to test the idea.

What were the results of your experiment?

 

[boydster]

The experiment was from 4 years ago and the poster you quoted hasn't posted anything here in more than a year and a half, so he may not get back to you on this one

 

[ae4853t]

Right. Knew it was old, but was browsing and just curious as to the results.

 

[therealmrpillay]

Ah! It's not a matter of disliking your explanation! I certainly did not mean to offend. I was just looking for a bit more of a scientific explanation than "Oxidized beer is not yummy" I was merely conjecturing and offering my thoughts on the situation

Yes I aswell appreciate the question. We are taught that agitation, heat etc naturally speed up reactions.
I mean would you just add a few teaspoons of sugar to a glass of water and wait 30 years for it to dissolve.
Also, what effect would this have on the end product is as good a question.

 

[treekiwi]

Just another point of reference......about 35 years ago I bought a keg off a guy who turned our to be the recently retired head brewer of one of the biggest breweries in New Zealand. He had just built a fermentation system for his home brew that incorporated a recirculation system during fermentation. He told me it was very important to keep everything stirred up. Oxygen would not be a problem as it was a closed system. Just an fyi FWIW. Cheers.