One beer two yeasts, but how?

[disasterjustavoided]

I'm planning on making a batch of English Mild and splitting it in two at the fermentation stage to litterally pitch two yeasts against each other, a nottingham (dry) and WLP037 (liquid) to see how they differ. I do have two fermenation bins but both are 30L and I'm a bit concerned there will be too much space at the top of the bins with just 10-15 litres in both. Will this matter too much?

I'm wondering if mashing to a higher OG in my 5 gallon set up, then watering it down at fermentation stage might do the job? Any other suggestions so I don't have to have 2 brew days for essentially the same beer?

 

[Matt3989]

3 gallon fermenters are fairly cheap, if you wanted to go that route. The watering down will work too, just use good clean water (you can refrigerate it too to cut down on chilling times), plus you'd end up with more beer!

the fermentaters you have will work though, your beer will produce a layer of co2 over itself, so even if it doesn't dispel all of the oxygen from the bucket, it'll still be protected (co2 is heavier than o2). And the airlock will still keep any bad guys out. Just don't move the fermenters around once you've pitched your yeast, you don't want to disturb your co2 blanket and end up with cardboardy oxygenated beers.

 

[itsme6582]

It'll be fine. You want oxygen at the beginning of fermentation and the head space will quickly fill with CO2.

Try the can I mash it calculator at rackers.org to find out your maximum ammount of grain. Then, you can add water to the fermentor and then correct your gravity with malt extract.