Fermentation

[SteveB.]

A question on fermentation, I have a modified refrigerator that I use for my fermentation so I can control the fermentation temperature.
Normally I use a 5 gallon plastic bucket with a lid and airlock fitted to ferment the wort in the fridge.
I have been thinking that as the fridge is sealed when closed do I really need to fit the lid and airlock or could I just leave the lid off the bucket and 'open ferment' as it where.
This would stop the airlock blocking and making a mess on those particularly mad vigorous fermentation's.
What do you guys think? Would there be any problems?

 

[Galena]

In my limited experience there is still a chance of infection inside the fridge, you are after all going to be opening the door fairly regularly, I think open fermentation's are best with yeast that creates a high Krausen and so gives a cover for the brew. Why not go for a blow off tube into a bottle of Sanitiser instead of a normal airlock? that's what I do anyway.

 

[Graz]

I wouldn't, especially in the early stages, there's still air in there which could have all sorts in it, wild yeast, bacteria, you name it.

However I don't use airlocks, I have a lid on an then just crack it open enough so the built up CO2 can escape. Never had an issue doing this and for all but the most violent fermentations don't get any mess with a 25L bucket.

 

[FirebladeAdam]

I saw a video recently that explained the the layer of Co2 on top of the fermenting wort protects it from airborne bacteria and yeasts. I have a toddler so I use an airlock!

 

[terrym]

There are all sorts of moulds and organisms within a fridge, unless they are effectivle sanitised on a regular basis. That's why sometimes they go black inside if closed and not cleaned regularly. Leave the lid on the FV with your airlock just like you would anywhere else.
As for the protective 'blanket of CO2' its more or less a myth in my view under some circumstances. Why? The amount of CO2 produced during a normal fermentation is significant and will purge out any air over time once it gets going so that the headspace is CO2 rich. However when the fermentation has finished and little or no more CO2 is being produced and things have settled down, if a homebrew FV is left open, air will slowly but progressively dilute the CO2 at a micro level, until the headspace is effectively air rich. So although initially there will be a concentraion gradient of CO2 to air sooner or later that disappears. That's why homebrewers are advised to 'keep the lid on' wherever practicable. Commercial brewers with open fermenters do things differently, That's why they don't get concerned about this.

 

[SteveB.]

Thanks guys for all your feedback. I see that it is a good idea to maintain the CO2 layer above the fermenting wort and also help keep out any nasties lurking in the fridge. With that in mind the lid will stay on the bucket.