How to carbonate in the BREWHA 4-in-1
The BREWHA 4-in-1 fermenters are designed to withstand up to 14.9psi of pressure. This is enough pressure to fully carbonate beer, and once carbonated, it is ready to serve.
The beer can be carbonated in the fermenter through force carbonation with a CO2 tank once fermentation is complete, or, with care, the beer can be naturally carbonated by capturing the gas released during fermentation.
Whether you are naturally or force carbonating, it is VERY IMPORTANT to always have the Pressure and Vacuum Safety Valve attached directly to one of the lid ports. If capturing the gas during fermentation, it is recommended to use a blow off hose until late in fermentation (e.g. when the gravity is around 1.020—a lower starting gravity with a small head space, and a higher starting gravity with a large head space) to reduce the risk of over pressurizing and damaging the tanks. While the pressure relief should let any excess gas off, waiting until your gravity is lower, will help minimize risk in the unlikely event of a relief valve failure (it is advised to regularly inspect the proper functioning of your safety valve). On the second 1.5" lid port, a valve should be attached, then a 1.5" tee is recommended, with a pressure gauge (or spunding valve apparatus) attached to the vertical side of the tee (1/4" thread pressure gauges can be purchased here and can be connected to a 1.5"TCx0.25" coupling), and a Fermenter Gas in Post attached to the horizontal (even if naturally carbonating, the Gas in Post will be used to add CO2 volumes if fermentation does not deliver quite enough and/or to maintain gas pressure when racking to kegs lowers the beer level in the tank; removed from the tank, this tee setup can also be used to test a Pressure and Vacuum Safety Valve to ensure it is functioning properly). If force carbonating, carbonating stones can be used (customers have reported that attaching the BREWHA Aeration Stone to the racking port works well and the tank is fully carbonated in 48-72 hours when held at 5C/41F), however, adding CO2 from above is not much slower, will eliminate the risk of gas stirring up any sediment/yeast that has settled out, and reduces the amount of flavor and aroma compounds that might be scrubbed out of the beer by gas bubbles. Gas pressure charts (see example at bottom of the page from Brewer's Friend) inform the brewer what pressure to set the regulator at, relative to the temperature of the beer and the desired final volume. For most ales when crashing to 4C/40F this will mean the regulator should be set to 12psi although styles like stouts will be lower and a few styles that require higher pressure will need to have some gas added in the keg as the fermenter pressure limit is 14.9psi (the relief valve should be tested regularly to determine its cracking/opening pressure and the regulator should be set below this value to ensure gas is not wasted; regulators should also be tested regularly and higher quality regulators will allow more accurate control).
Once CO2 is added (either naturally or forced in), the Chiller can circulate cold water through the jacket to reduce the temperature of the beer (a removable neoprene insulating jacket can be installed at this point to help the beer get within a few degrees of freezing under standard room conditions)—this will reduce carbonation time and allow more volumes of CO2 (CO2 dissolves more readily at lower temperature) and help remaining yeast to drop out of suspension (crash cooling). Even if not wanting to carbonate in the fermenter, maintaining a few psi of pressure in the fermenter when cooling will eliminate the risk of a vacuum forming as the pressure offsets the vacuum created by water/beer shrinking as it cools.
Once cooled, yeast can be removed through the bottom/dump valve and the racking arm flushed out to remove any yeast settled in there and the beer can be transferred to kegs for serving (keep the CO2 connected to the fermenter while kegging to maintain pressure in the tank as the beer level drops — this will help maintain carbonation levels and reduce foaming in the fermenter which can stir up residual yeast).