Equipment question.

[Pitbull-brewer]

I want to do a one or two gallon batch for my next beer, but my primary fermenter is a 5 gallon tube. Will this ruin my beer? If it will what is the most cost effective way to get a smaller fermenter.

 

[Backporchbrewery]

The CO2 released from the yeast during fermentation should fill the head space in the fermenter making it fine. Just shoot for 1/2gal bigger batch size to leave room for trub when you rack off to bottle.
I know the food-grade Lowes 5gal buckets are great for 3gal batches and only run about $4.