We start with the most common type: filtered, artificially carbonated bottled beer.
“1. Carbonated and filtered bright beers; light ale and brown ale, together with stronger special ales. These are usually conditioned in bulk and carbonated. Fine filtration is usually relied upon to give a product which although not always completely sterile has a reasonable shelf life. In some cases the beer is pasteurized as an additional safeguard against biological haze, but this may have the effect of accelerating the onset of non-biological haze.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, page 331.
You’ll note that they specifically mention two of the most popular bottled beers down the pub – Light Ale and Brown Ale. There may have been stronger Brown Ales that were bottle-conditioned at some point, but I’m pretty sure Light Ale was always filtered and carbonated. I’m surprised that these beers weren’t always pasteurised by the 1950’s. Though bottled beers sold through pubs weren’t in a very long supply chain and wouldn’t have needed a shelf life measured in months.
Next is a fairly similar type:
“2. Stouts produced in a similar way to the above, that is conditioned in bulk and carbonated. These will either not be filtered at all or will be only roughly filtered, so that they will contain yeast and possibly other organisms. If they are of the non-sweet variety they may have a reasonable shelf life without pasteurizing, but there is always the liability for yeast growth to cause excessive condition, or growth of bacteria to affect the soundness. Sweet stouts, however, almost invariably need pasteurizing, as otherwise fermentation will occur in bottle, giving excess condition.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, pages 330 - 331.
Much the same as type one, except not filtered so much. It’s pretty obvious why this would be dangerous in a Sweet Stout – it was likely to start fermenting again in the bottle. A good way to produce bottle bombs. Interesting that this is mentioned as being a method specifically for Stout. In an opaque beer like Stout, there wasn’t the same need for cosmetic filtering as in a pale beer.
And finally the proper way of making bottled beer:
“3. Naturally conditioned ales and stouts. These are first matured in cask or in bulk, or first in cask followed by further maturation in bulk, then bottled off with sufficient yeast and enough slowly fermentable matter to give some further fermentation in bottle, thus producing the necessary condition. These require further cellar storage of from three to four weeks after bottling and they require careful handling to ensure that they reach the consumer in satisfactory condition. As already mentioned, relatively few breweries produce their own beers of this category, preferring to bottle well-known brands. We shall deal with the three categories in order.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, page 332.
This method was already becoming limited to a few specific brands. By the time I started drinking in the early 1970’s just six naturally-conditioned bottled beers remained: Guinness Extra Stout, Worthington White Shield, Eldridge Pope Hardy Ale, Gale’s Prize Old Ale, Bass Red Triangle (actually the same beer as White Shield) and Own Ale, a beer from the first new brewery for decades, brewed on pretty much a homebrew scale. Amazing to see how much of a comeback this type has made. I’m sure it would have surprised Jeffery.
The process he describes - maturation in casks, then bottling with live yeast and allowing the beer to carbonate naturally – is much the same method as employed by Bass from the mid-19th century onwards.
Next we’ll be looking at artificially-carbonated beer in more detail.