Barrel Problem

supernova

I have just finished primary fermentation on a batch of Edme German Lager last night and barrelled it.
Im brewing it in my kitchen and its quite cold in there so i decided to place the barrel on my heating tray for a couple of days to make sure secondary fermentation started.
I checked on the barrel earlier, only to find that lager had leaked out from the tap and leaked onto my heating tray.
I moved the barrel to my sink and tightened the tap as far as i could but the barrel was still hissing and leaking lager out. I assume this was because there was that much pressure, it had nowhere else to go.
I then made a potentially rash decision and opened the tap to let some pressure out.
The brew practically exploded out of the tap then finally poured out at a normal rate.
I then managed to tighten the tap even further and placed the barrel back on the (thankfully undamaged) heater tray.
Im now worried that because i opened the tap, it will have let air into the barrel and contaminate my brew!!
Is this the case and should i start again please?

HBO_Staff

The barrels are capable of holding a lot of pressure, and the weakest points are around the lid and around the tap. The taps must always be checked and tightened if needed, hand tight is not enough due to the pressures involved. We always recommend to give them a nip up with a spanner or pair of grips before use so that the black washers begin to compress and this ensures a tight seal. You could have very gently cracked the lid open to release any excess pressure if you felt it was needed, as this wont let any beer out. Your concern about the air at this early stage in the barrel is not necesary, as the brew continues with it's secondary fermentation it will continue to carbonate and build up pressure, although at a slower rate than when it was on the heater tray. The volume of air inside the barrel with a full brew will be relatively small, and then mixed and partly displaced by the gases produced will be reduced and minimal. The brew will undoubtedly be fine so leave it to ferment in a cooler place for a while now. The barrel has a safety feature to release excess pressure, although sometimes it can build up quite high before it does this, it would be worth checking that the underside of the cap is clean and not blocked in any way before it's next use. The rubber 'band' you can see on the top of the barrel is designed to be forced open and reveal a small hole in the brass valve from where excess pressure can escape as needed, the band then tightens back into place and reseals once the pressure is reduced enough. Sometimes for peace of mind people who are concerned about the pressure do just very slowly and carefully crack the lid open slightly by unscrewing it, release a small amount of pressure and re-tighten it. To avoid excess pressure it is also important to make sure that the primary fermentation is fully complete and the hydrometer reading is nice and low and constant, and not to over-prime the barrel for secondary fermentation. The heat in this case will certainly have contributed to the quick build up of pressure 

supernova

Great stuff. Thanks.
Have now removed the heating tray, tightened the tap and left it in a cool place.
I have got some CO2 bulbs just incase as the 1st batch i brewed last month ended up flat as a pancake due to a combo of far too much priming sugar and (i think) not enough carbonation pressure in the barrel.
Fingers crossed!!

HBO_Staff

One thing we recommend is that you fit the cap with a brass injector to the barrel from the beginning, rather than use a plain vent cap and then swap it over to the injector version later. This means you don't have to open the barrel and let any air in half way through the brew. You may find it needs additonal CO2 depending on consumption, temperature and the particular brew, if the flow slows down to a trickle from the tap, inject one CO2 bulb and continue to dispense as usual. Then repeat later if needed, rather than injecting more than one CO2 bulb at once. To help with carbonation it is good to leave the barrel for a few weeks to condition and this will help the priming sugar. Most brews improve with time, the flavours will also improve, so if you can leave it a while it helps the brew taste it's best