Pressurized fermentations are becoming increasingly popular, and for a good reason. Some of the benefits that you gain from fermenting beer under pressure are: Lower ester production, being able to ferment at higher temperatures without producing off-flavors, and having your beer carbonated by the end of fermentation (rather than carbonating separately for over a week!). Called Unitanks because you can use them for both fermentation and carbonating. You can serve beer directly from uni tanks, counter pressure fill bottles or easily transfer beer into kegs using pressure.
Fermenting lagers under pressure is a huge benefit of unitank. When yeast ferment under pressure, the production of fruity esters is greatly reduced. This can allow you to brew a lager at 70F an obtain traditional lager flavor. All of the fementers listed below also allow for fermenting under no pressure or greatly reduced pressure which is preferrable for making ales where the fruity esters are an essential part of the flavor profile.
With have a continually growing selection of unitanks to choose from including Ss Unitanks, the Fermentasaurus, the Blichmann Cornical, and the WilliamsWarn BrewKeg. Other products that you'll need include a CO2 tank and regulator, the appropriate connection fittings, tubing, etc.