This was effectively a streamlined version of natural conditioning. The main aim being to speed up the process and hence leave less capital tied up in conditioning bottles.
A quicker conditioning in the cask was encouraged and the beer fined before flattening prior to bottling. The store where the bottles were conditioned was at 60º and 70º F to speed up the process.
Beer produced by this method was satisfactory as long it was consumed quickly. When stored for too long it was likely to develop a thick sediment and become unappealingly cloudy.
In this method, beer was carbonated by injecting CO2 prior to bottling. Most brewers purchased cylinders of gas for this purpose, though some preferred to make it themselves. No-one seems to have collected the CO2 naturally produced during primary fermentation.
The big drawback of bottled beer produced this way was that it started to throw a sediment after just a few days. The shelf-life could be improved by filtering before bottling, but it remained limited. Unless you could guarantee that the beer could be sold and consumed quickly, this wasn’t a suitable way of bottling. It did have the advantages of speed and reducing inventory of conditioning beer.
Quick chilling and filtering
Originally developed in the USA, this method entailed chilling beer quickly to around freezing point (26º - 36º F), which caused a haze to be precipitated. Carbonation and filtration followed, after which the beer was bottled.
Though quick, this method had the disadvantages of producing beers with a short shelf life and sometimes giving them an unpleasant flavour. Generally, the slow chilling method which follows was considered to be superior.