Conical fermenter and avoiding contamination

[jonncfc]

Hi,
I'm new to the forum and am just about to acquire a conical fermenter. I know that one of the advantages of this design is the ability to remove the yeast plug after primary fermentation but I wondered whether opening the bottom tap to drop this out results in air being pulled in through the airlock. If so, isn't there a risk that the beer could become contaminated and infected?

[barneey]

Liquid out = gas in.

So if it is of concern, either fit a sterile filter whilst dropping the yeast, connect a co2 supply (or other gas). Personally I normally just remove the air lock.

Just remember to take out the air lock whatever method used otherwise it will suck the thing dry.

If you ever cool towards the end of ferment again be careful that the beer doesn't absorb the co2 in the head space and then start sucking on the airlock.

[TheSumOfAllBeers]

What Barneey said. In fact I would recommend that you ditch the airlock and install a blow off tube instead.

A possible way of getting round this is to install some kind of CO2 capture device along with your blow off tube. A gas bladder on a tee connector would work. Whenever you dump or chill your gas will be drawn from there rather than the atmosphere or your star San reservoir.

[jonncfc]

Many thanks for the advice, guys. Greatly appreciated.

[TheSumOfAllBeers]

Suck back is a bigger deal in a rigid conical - more so than a flexible plastic bucket.

The best option by far is keeping the internal pressure at atmospheric pressure with a sterile co2 source once active fermentation has ceased, this can also double as a dispense under pressure system if your conical supports that.

[guypettigrew]

This will probably cause laughter all round, but I just take the end of my blow off tube out of the bucket of water it sits in during fermentation. When I harvest the yeast air sucks back in. Then I drop the tube back in its bucket.

But I don't worry about it. I work on the basis the beer is still fermenting so it won't take long to push the air back out again.

When I cool the beer at the end of fermentation I loop the blow off tube into a 'U' shape and pour a few mls of Starsan in it. The air which is sucked in has to bubble through the Starsan so I like to think it's fairly safe by the time it reaches the space above the beer in the fermenter.

However much air the beer comes in contact with during these processes seems minimal to me in comparison with the amount of air the beer encounters when I drop it into the King Keg!

Guy

[TheSumOfAllBeers]

The problem is oxidation as you crash cool. Once the internal pressure is lower than the exterior, you will suck air into the FV when you take samples, drop yeast or dry hop.