60L fermentor

[i-a-n]

Hey guys,

A really quick question: is is ok to use a 60L fermentor for regular 23L sized brews?

I have a 60L fermentor but dont want to do a double batch as ive just started brewing.

thanks!

Really quick question.

PMSL

you opened a can of worms amigo.

 

[calobes]

Really quick question.
PMSL
you opened a can of worms amigo.

lol yeah seems that way. I had no idea I promise!! I opted out, everything became a bit to confusing for a newbie.

 

[HBHB]

There's 1 way to find out. Who's got a Photoacoustic spectroscope laying around gathering dust?

 

[Batz]

There's 1 way to find out. Who's got a Photoacoustic spectroscope laying around gathering dust?

Sounds like something I rather the doctor didn't use on me. :blink:

 

[Greg.L]

There's no controversy really, it's just a choice between the "she'll be right" brigade and the " better safe than sorry" camp. The only controversy is when the "she'll be right" brigade try to make out their method is perfectly safe.

 

[StalkingWilbur]

Ohh, Greg...

 

[i-a-n]

How about filling the fermenter then turning it upside down so the "air" gap is at the bottom?

 

[Yob]

The only controversy is when the "she'll be right" brigade try to make out their method is perfectly safe.

all evidence aside that it isnt the end of the world yeah?

Coz you know... every second ferment is oxidized and **** right?

 

[GrumpyPaul]

How about filling the fermenter then turning it upside down so the "air" gap is at the bottom?

Is there any scientific evidence to prove that if I did this my gladwrap wont break when I turn the fermenter upside down????

 

[Grott]

Now GrumpyPaul, you should know that the molecular contact of the gladwrap with the wort will cause the ionization of ..................

 

[mofox1]

Is there any scientific evidence to prove that if I did this my gladwrap wont break when I turn the fermenter upside down????

It's probably got something to do with partial pressures... h34r:

In all seriousness to the original poster, try it and see. The worst thing that could happen is that you might need reassurance that it's okay.

You are obviously more convinced by all the people on this forum who reassure each other that a huge headspace is fine.

And we're here for you. :wub:

 

[pcmfisher]

Greg.L, on 02 Aug 2014 - 12:52 PM, said:Greg.L, on 02 Aug 2014 - 12:52 PM, said:

There is this thing called google, if you search oxygen permeability of hdpe plastic you might get some results. Most fermenters are hdpe.
One site gives a figure for hdpe of 4000 cm3-mil/m2/day but I am not sure what the thickness is. The thicker the wall of the fermenter the less permeable it is but if you use ldpe it is quite permeable.

As I said the wort itself is more resistant to oxygen but the headspace has a big impact. Oxygen will also get past an o-ring but very slowly, an o-ring is a hell of a lot better than gladwrap and a rubber band.

OK.
I have seen figures of less than 2000 cm3/mil/m2/day but we will use your 4000.
BTW, /mil is the thickness ie 1 mil = 1/1000 inch. Therefore 1mm = 39 mil.

60 litre fermenter with 20 litres of beer has 40cm of head space at 38cm diameter and I reckon it is about 2mm thick. That's about 0.6m2 of surface area inc the lid above the surface if the liquid.
4000 / 78 x 0.6 = 30cm3 oxygen per day.

A standard 30 litre fermenter has 1/3 of that surface area above the liquid so that makes it 10cm3 per day for that size.



If however you had a 25cm dia bit of glad wrap as a lid.
That is 0.05 m2 but glad wrap is about 0.5 mil thick. (That's mil not mm)

So, 4000 / 0.5 x 0.05 = 400cm3 per day just through the glad wrap.

I don't know if 400cc is a lot of oxygen to pass into a fermenter each day, but I would reckon if people using glad wrap can make beer indistinguishable to those using a lid, I will stand by my original comment.

 

[Blind Dog]

So, 4000 / 0.5 x 0.05 = 400cm3 per day just through the glad wrap.

I don't know if 400cc is a lot of oxygen to pass into a fermenter each day, but I would reckon if people using glad wrap can make beer indistinguishable to those using a lid, I will stand by my original comment.

It’s a huge amount.

Even assuming that's all the oxygen that gets in there and assuming only 1% gets dissolved into the beer, and assuming that we only have to worry after fermentation is largely complete (so say for 3 days only) that works out as 600ppm of oxygen in 20L (0.4L x 1% x 3 x 1,000,000 / 20L).

The saturation point of oxygen in water is just 14.6ppm at freezing and less than that as it gets warmer.

So I’m not going to drink my beer anymore. I'm going to breathe it. Marvellous

 

[Greg.L]

Your calculations seem good but the permeability figures were for hdpe. The figures for gladwrap are a lot higher so probably multiply your figure for gladwrap by ten. I wouldn't be surprised if as you say the figures from that site are on the high side. HDPE fermenters work fine when full because the live yeast can soak up the o2 without problems. It is the o2 in contact with the surface of the beer that causes the problems.

 

[seamad]

If your theory on headspace were correct then gladwrappers would have an almost infinte headspace then because of the permability, and would therfore always have oxidised beer ?

 

[GalBrew]

Glad wrap is highly permeable to oxygen, far more than HDPE. Whether that will result in noticeably oxidised beer I can not tell you.

 

[Greg.L]

My main concern with headspace and gladwrap is the potential for infections, but it can't be good in terms of oxidation either. The basic principle is to always try to minimise the oxygen getting in the fermenter, oxygen contact is one of the variables homebrewers have control over, along with things like temperature, yeast strain, volume, O.G. etc. If you can control a variable then you should be trying to optimise it.

 

[Yob]

Whether that will result in noticeably oxidised beer I can not tell you.

I dont seem to get those comments from Comp entries from people trained to detect that sort of thing.. I dont seem to get that from Club members who know of such things.. I dont seem to detect it myself, I know what oxidised beer tastes like...

Seriously.. Every second score sheet would have to have a big oxidised through it if it was a real issue.

 

[Greg.L]

In my opinion most infections are caused by oxygen in the headspace. It's a misconception that infections are caused by poor sanitation, infections are usually aerobic organisms and need oxygen. Of course, sanitation is one of those variables, like oxygen exposure, that homebrewers have control over. Obviously it is better to use a clean fermenter than a dirty one, just as it is better to have a small headspace than a big one. It would be foolish to use a dirty fermenter when it is so easy to clean it, and it is foolish to use a fermenter that is too big when it is so easy to get the right size.

 

[StalkingWilbur]

Do many people share this opinion?