Yeasticide

[batfastard]

Gents (and any ladies),

I want to kill off residual yeast at the kegging stage to stop any further fermentation.

I'm brewing petty much straight kit + kilo and kegging into 19l cornies, carbonating with a co2 bottle.

I'd expect some kind of sanitiser would do it without impacting the flavor, but which sanitiser?

I use Milton's to sanitise generally, would a dose of that in the keg sort things out? If so, how much should I use?

 

[Jack of all biers]

You're kidding right?

Miltons is chlorine bleach and 16% salt. Put that in your beer in any amount and you will know it. You'll end up with band-aid flavoured salty c**p.

Any way, no chemical sanitizer will kill off the yeast in beer without affecting flavour. You'd need too high an amount to ensure the yeast were killed in 18-19L of beer that it wouldn't taste of beer you'd want to drink thereafter.

I question why you want to do this in the first place. If your beers are becoming overcarbonated in the keg, it may be because they hadn't fininshed fermentation in the fermenting vessel, or it may be that you're overcarbing with your CO2 bottle without knowing it (it's easy to do). Both of these are easily overcome with depressurisation over a period of time and repressurisation at correct carb pressure/temperature.

If you are dead set on killing off the yeast in keg, then one way to do it is pasturisation. Heat the keg up externally (in a bath for example) to 60-65C and hold it for 30 mins, but this requires a slow heat up to ensure the entire volume of the keg get to that temp. The hoter it goes the shorter the time. 72C will only need to be held for 15 seconds, but again the whole volume of the keg. I wouldn't recommend doing it as it is impracticable and to my mind likely to affect flavour of your beer due to killing one of the main conditioners able to eat up extra sugars and off flavour compounds over time. Matter for yourself however.

EDIT - or you could get an in-line filter and filter out the yeast on the way to the keg. But if the issue is that the beer isn't finished fermenting, then you will likely end up with a poorer tasting product.

 

[batfastard]

I had the problem with a batch of cider I made.

It tasted ok at kegging, but as time went on the yeast kept going making it more and more dry even though it was refrigerated. I ended up having to back sweeten a couple of times.

 

[dave_h]

Maybe use some less fermentale suggars like lactose?

 

[5teve]

From what I understand the way this is typically done in commercial cider/wine etc is the use of preservatives to kill or make yeast sterile such as Potassium Sorbate (202), Sodium Metabisulphite (223) or Potassium Metabisulphite (224).

These are usually added to the fresh juice prior to fermentation to inhibit any wild yeast taking hold before being inoculated with the desired yeast strain, or end fermentation prior to full attenuation for a sweeter finish.

Or as Jack of all biers pointed out, you could use pasteurisation, but that's not so convenient at home. I guess if you have a coil or plate chiller you could kind of use that in reverse as a heat exchange to heat the juice to your pasteurisation temp on the way to the keg?