Before crash cooling, you can use the Pressure Transfer Kit to apply 0.5 psi of CO2 to the top of the fermenter to serve as a CO2 blanket that protects the brew in the fermenter as the beer contracts during the cold crash process.

This phenomenon is caused by the thermal shrinkage of the beer as the temperature is rapidly dropped. An added a blanket of CO2 to the top of the fermenter stops outside air from getting sucked into the fermenter as the beer contracts during rapidly cooling. 

To cold crash using the Grainfather Pressure Transfer Kit, securely attach the device to the top of your Conical Fermenter and adjust the valve to apply 0.5 psi of CO2 to form the above mentioned CO2 blanket on the top of the fermenter.  Keep the Pressure Transfer Kit attached to the fermenter for the duration of the cold crashing process - until the temperature of the beer inside has reached around 4°C (39°F).

Once you have reached the desired temperature through cold crashing, you can remove the Pressure Transfer Kit and reapply the airlock to the top of the fermenter, or you can directly transfer your beer to a keg.

If you are not using the Pressure Transfer Kit or another CO2 recovery device to rapidly cool your beer, you can cool your beer slowly by 3°C (37.4°F) per day.  This slower rate of cooling will allow equilibrium between the pressure in the fermenter and the outside pressure, and stop air from getting back into the fermenter as the temperature drops.

Alternatively, use a CO2 recovery device. 

Follow this link to the Pressure Transfer that we have available on our website. *Not all products available in all markets.