Minimum beer amount in a pressure barrel

[beerfountain]

I have a 10 litre pressure barrel (like the standard white plastic barrels but mini).
I've been thinking of doing a small all grain, 5-6 litres something like that, so I can test out some beer ideas, would this be ok in a mini 10L barrel or will there be problems with there being too much space?
I could bottle it instead of course but I find the barrel so much easier.

Also, while I'm here, does anyone know the minimum amount you can put in a standard 5 gallon/23 litre barrel? Could you put say 15 litres in there instead of the full 20+ litres? I've put 19 litres in there before and bottled the rest when doing a kit. Just wondering if I can get away with putting less in there if I wanted to do a smaller all grain/partial/extract brew for example.

 

[Hoppyland]

Well, it's a long time since I used a pressure barrel. These days I tend to bottle, or (only recently) use Corny kegs. Anyway, here's my view.
If you put a relatively small amount of beer in a pressure barrel, then there will be a lot of headspace - and therefore a lot of air - above the beer.
Two problems here. Depending upon how long the beer stays in the barrel, the oxygen in the headspace will definitely have a "staling" effect on the beer. A slow degradation, but it will happen in my experience.
There's also the problem of infection. A lot of potential infection organisms need oxygen to grow, so a big headspace full of air is ideal for them!
Two ways around this occur to me. You could transfer the beer whilst it is still fermenting quite vigorously, or possibly wait until fermentation is subsiding and then transfer with a decent hit of priming sugar. Either way, the beer should keep producing CO2 & probably drive off enough O2 to protect itself. But, it will then take longer to mature.
Otherwise, transfer to barrel & then purge your headspace with CO2 from a cylinder. However, unless you've got a large cylinder (such as welding-size, 6kg of CO2), this could work out quite expensive.

 

[beerfountain]

Thanks for the reply.
I think I will have to up the amount I brew to 8 litres for my 10 litre barrel in that case. It probably makes more sense to do that. If I ever do less than that, I'll bottle them as it just seems safer.
If I do a 15 litre brew, I'll carry on doing what I did once before, barrel 9/10 ish liters in my mini barrel, and bottle the remaining 5L.

 

[MarkBowie]

As far as I was aware (I maybe wrong) I didn’t think it mattered as long as you purged the head space with CO2 after?

 

[Hoppyland]

As far as I was aware (I maybe wrong) I didn’t think it mattered as long as you purged the head space with CO2 after?

Yep, I'd agree. The problem arises if you have a large headspace and you don't have a large/cheapish source of CO2 to purge. I use 6kg welding-gas cylinders, so the cost is minimal distributed over many brews. But, if all you've got is small cylinders or bulbs then it is not a practical option in terms of cost.

 

[brumbrew]

I've just opened my 10 litre pressure barrel. Got two good pints then nothing. Put a shot of co2 into it and immediately noticed a leak around the copper fitting on the top. Tightened it then added another shot.

The excess pressure came out the leak until it settled. Managed a further 4 pints until it started to draw air back through the tap and 'glug' the beer out.

I've been warned about pressure barrels but thought I'd give it a shot as I could get one cheap.

I've not given up yet. But I've got to do something with about 8 litres of beer now. And I've got work at 5 in the morning.

Guess I'll risk it and take it apart tomorrow in the empire of dirt (the shed) whilst trying to consume the remaining content's.

They always need a little jiggery-pokery to get them running right so I'm told. I thought I'd take the risk before buying one of those shiny dark farm kegs.

pressurise it with water. Leave it over night and see how many pints you can draw off before it 'stalls' 'vacuums'