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Brewing Topics => Brewing Discussion => Topic started by: Wildrover on November 24, 2011, 07:49:10 AM

Title: Top vs. Bottom Fermentation a Myth?
Post by: Wildrover on November 24, 2011, 07:49:10 AM
The more I think about it the more the difference between a lager yeast fermenting at the bottom of the vessel and an ale fermenting at the top seems like a poor distinction.  Anybody who has ever watched their beer ferment knows that the fermentation occurs at any point in the fermentation vessel.  Its not like the ale yeast are sitting at the top just waiting for random sugars t float up.  So, having said that, I'm beginning to believe that the true distinction between lager and ale yeast lie not in where they ferment but how they ferment.  The real difference lay in the temp where the yeast ferment the best which has subsequent influences on things like speed and the production of yeast driven flavors etc. 

So, if I'm correct, where does this top vs bottom fermenting myth come from?

What say you, I'll hang up and listen. 
Title: Re: Top vs. Bottom Fermentation a Myth?
Post by: DaveinPa on November 25, 2011, 01:44:20 PM
I think the temperature IS the reason.  The higher temperature of ales causes a high level of activity and tends to stir things up a lot which gets some of the yeast to rise to the top.  The lower level of activity of lagers tends to let the yeast sink more - basically what cold crashing does.  Just a guess based on observation.
Title: Re: Top vs. Bottom Fermentation a Myth?
Post by: merfizle on November 25, 2011, 03:14:11 PM
It depends who you ask.  Some say it's what yeast you use.  Others, if you lager it.  Others still...it has to be both. 
Title: Re: Top vs. Bottom Fermentation a Myth?
Post by: Rusty Nails on November 25, 2011, 07:21:20 PM
Top fermenting vs bottom frementing, and why: (IMVHO)
1) Tradition.
2) Laws. In some states 'ale' is defined by alc. %
3) Saccharomyces cervisiae & Saccharomyces pastorianus are too hard for the normal person to remember
4) Ditto with the sugars melibiose & raffinose
5) Tradition
You have valid arguments, however. What would you call them, that would allow the non-beergeek to understand?
Title: Re: Top vs. Bottom Fermentation a Myth?
Post by: Maine Homebrewer on December 03, 2011, 10:40:29 AM
The batch before last used Safale US-05 at 60-64 degrees, and it had a good four inches or more of foam on top.

Last weekend I pitched Saflager S-23 into a batch at 58-62 degrees, and it might have maxed out at an inch of foam on top.