As I start planning my pico brewery, I've been thinking about fermenters. I'd love some thoughts on ways to ferment 1/2 and 1bbl (15.5 - 31 gallon) batches. Options for when price is and is not a concern would be great.
I ferment 10gal batches in a 14gal conical but have been looking at this kit from Brewers Hardware recently to add some capacity at a better price.
The single 1bbl vessel .v. two 1/2bbl vessels is not going to affect yeast pitching quantities, you are just going to take the same original starter and split it between the vessels. The space saving and cleaning labor savings would be quite significant over the long run though.
When you start modeling your production expenses, you will quickly see that at pico brewery scale, labor costs are the most significant component of your costs. This shifts quickly to ingredients and then to energy and space as you move up in scale. Forecast and estimate your production volumes carefully and realistically. You could find that investing in bigger equipment will pay for itself quickly if your brews are in demand quickly. If, that takes longer, then making smaller investments in pilot-scale equipment and brewing more frequently (2-3 batches a day) might make more sense at the beginning.
I use a Sanke keg for fermenting my 10-15gal batches, works great. You can also look into using plastic conical fermentors. You can get them in 15-500+gal sizes.
I'm looking at getting a 15gal and a 65gal.