Same beer: Cask vs Keg

A couple of points here, Oliver from the Tapsters Promise would like us to explain the difference between types of kegs and how a beer is kegged, then one of our very good customers asked why the price of our bar’s keg beer was different to our handpulled prices.

I’ll have to tackle this in parts, first off the different types of Kegs.


  • Beer in bag system, the gas you use to serve the beer never comes into contact with the product inside, serving gas collapses the internal bag pushing the beer out.
  • If the brewer gets the carbonation level right when filling the beer should stay that way if handled correctly.
  • Can be served using compressed air or co2  (Carbon dioxide Gas).

Regular kegs, Dolium, Stainless Steel, Molded Plastic, Ecokeg etc:

  • As far as I am aware all these types of kegs require co2 to serve as the gas its self is directly in contact with the beer inside the keg.
  • Not a lot to say about this unless I let my opinions start talking, there is more chance of contaminating the beer or gaining or losing carbonation in the pub cellar, if stored and served correctly there are no issues.

Now we need to talk about Carbonation and how it can be applied:

  1. Carbonation with external co2 in the fermenting vessel, conditioning tank or bright tank.
  2. Carbonation from natural co2 given off during fermentation with a pressure relief valve (Spunding Valve) set to a certain pressure during the later stages of fermentation.
  3. Carbonation in keg from adding sugar solution to the beer prior to filling kegs, the kegs are then kept warm for 7 to 10 days while the residual yeast in keg turns the sugar into natural carbon dioxide.
  4. Carbonation with external co2 added via the keg-coupler direct to each keg.

The Keg vs Cask price on our bar:

There is a rough rule of thumb, if a cask of beer sells for £80 per 40 Litres then a keg of the same beer will sell for the same £80 for 30 Litres, this is due to the extra cost & time involved in packaging (filling) kegs vs casks, I’ll show two lists so you can compare the way we do things.

Cask Only Packaging:

  1. Beer is fermented until the last 1 to 2 degrees of fermentable sugar are left in the beer (this aides cask conditioning).
  2. Beer is chilled down in stages, 17c for 24 hours, 11c or 4c for 24hours depending on whether we are to dry hop or not we vary the time cooling takes for whether it is going to be fined or unfined beer. Cooling beer is done via the glycol chiller unit which runs on electric.
  3. Cleaning chemicals are used to clean all pipework that touches the beer.
  4. All casks are cleaned externally and internally, casks are re-usable.
  5. After filling all casks you are left with a dirty fermenting vessel which will require cleaning with caustic cleaning chemicals.

Keg Only Packaging:

  1. Repeat steps 1 through 5 above with the extras below.
  2. Wait for two gravity readings the same which are 24 hours apart so you can ensure a stable Terminal Gravity (Negligible fermenation activity, there beer does not ferment further).
  3. Cool the beer further, slightly cooler and for a longer time, to ensure the appropriate clarity of beer is ready for packaging. (Steps 2 & 3 can tie up a fermentation vessel for up-to 5 extra days)
  4. Clean the tank and all pipework you are going to use to keg the beer from, again caustic cleaning chemicals are used.
  5. Buy carbon dioxide or sugar for priming, which is used to carbonate the beer.
  6. Buy the One-Trip kegs and snap on dust caps.
  7. Fill the kegs, each one is 30 Litres and take about double the amount of time it takes to fill a 40 Litre Cask.
  8. After filling all your kegs you are left with a dirty kegging tank which must, yet again, be cleaned with caustic cleaning chemicals.
  9. *Options* If the beer was directly carbonated with co2 the beer is ready for sale when the brewer feels it is right.
  10. *Options* If the beer was primed with sugar the kegs must been kept warm for 7 to 10 days while the beer naturally carbonates its self, we do this in our purpose built Warm-room using an electric heater to keep a temperature of between 20c-24c.
  11. Kegs are then cooled in our coldstore for a minimum of 24 hours before being available for sale.
  12. Sometimes extra branding, ‘Point of Sale’, Keg Badges will need to be purchased, we try to minimise this and use our regular pumpclips where we can though a properly made Keg Badge finishes the job off more professionally.

So that completes the comparison of Casked & Kegged beers with their associated production procedures.
Cask = 5 steps
Keg = 16 steps
When we price a keg beer for our bar we should not sell ourselves short as this simply wouldn’t be fair on us, our aim for next year is to ensure we carry this fair approach to our brewery-tap-served cask beers.

I hope that helps open drinkers eyes to why Keg beer can cost more than cask, Cask prices have been punished severely by the likes of Wetherspoons over many years and it is a growing opinion that Cask beer should be valued higher which would balance this entire Cask vs Keg pricing thing 😉

Talking of Keg beer, our naturally keg-conditioned Double IPA ‘Lupulonimbus’ 7.5% will be available in about a week after its warm conditioning.