Corny keg tips #1

#homebrew #homebrewing #cornykeg

Once the primary fermentation of a brew is complete I can then get onto the secondary fermentation and conditioning.

Secondary fermentation is what gives beer it’s fizz. Mostly I use a 19L corny (Cornelius Style Keg) for this.

First I put 128g brewing sugar (dextrose) into the corny, then 8 tsp liquid finings, some people use finings, some don’t, I do. What we want to happen is for the ye3ast that’s left in beer after racking to ferment the dextrose which gives out CO2, this gives the beer it’s fizz, trial and error lead me to 128g as the ideal amount for the fizz I want for most ales that I brew, I do adjust this for lagers and different types of beer, but for ales 128g is spot on.

Next with the corny open I connect the CO2 bottle and give it a 5 second burst of gas, why? because it pushes the oxygen out of the corny, we don’t want oxygen mixing with the beer as it will cause the beer to oxidise and taste “off” CO2 is heavier than oxygen so even though the lid is off and the corny open the CO2 is keeping the air out. I then syphon the beer in and fill to 18 Litres. Corny’s will hold 19L but you want some space in the corny after it’s sealed. after I have filled I put the lid on and check I have a good seal, I do this by slowly tilting the corny onto it’s side if no liquid escapes by the time it’s completely on it’s side then I have a good seal.

I then give the corny a good roll around on the floor to make sure the finings and dextrose mix in with the beer. I stand the corny upright again, then I connect my gas to the Gas-in port but I don’t open the valve on the cylinder. The reason I do this is because then the regulator will show me the pressure inside the corny and the reason I need to know the pressure is to check if the secondary fermentation is actually working. As a general rule the pressure usually go up to around 30PSI in 2-3 days and sits there, that’s it, beer is carbonated. Oh corny’s are rated for 130PSI so 30PSI is nothing.

Now we move on to the conditioning stage, fizzy beer is great but not if it’s cloudy so it’s a case of waiting for the finings and gravity to do their jobs and drop the remaining yeast to the bottom of the corny leaving a lovely clear beer. That’s what conditioning does.

How do you know when it’s conditioned?

Experience is the obvious answer, drawing off a sample is another. But wait the beer is at 30PSI and you really don’t want to be pouring out at that pressure so you will need to release some pressure via the PRV which of course also releases the CO2 that’s absorbed in the beer, something you don’t want to be doing until it’s ready to drink.

So, how to tell if you beer is conditioned without sampling it from the corny?
Well I brew in 23l batches which is what most kits are but I only transfer 18l into the corny leaving me around 5l in the FV.
Out of that 5l only 2-3l is usable as by this time your syphon is getting very close to the trub on the bottom of the FV and you don’t want that being out into your beer.

I have a lot of 1L clear PET beer bottles so I pop a sp dextrose into 1 then fill it up to 1L and put the cap on it. I then sit it next to or on top of my corny.
That way I can tell if my beer has cleared or or not, if it’s clear in the bottle then it’s going to be clear in the corny.

To clear fully usually takes around 3 weeks, you can clear quicker by cold crashing but I currently can’t refrigerate so I have to use time and gravity instead.

More tips coming soon

Steve Woodmore

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