Looking to increase brewing capacity without searching for more free houses or wholesalers? Looking for something to occupy those endless hours while wort mashes and boils? Then look no further than bottling your beer instead of casking it.

Bottled beers from smaller breweries are catching a popular imagination and may be due for a surge in demand. Even if it only acts as a promotion for brewery trips bottled beer is always a good promotion for your brands. As word spreads local interest may encourage more extensive production even leading to national sales.

Unfortunately bottling beer requires more control than filling with a tube. Moreover, bottle-conditioned beer has, at present, a limited market and is by no means a simpler process than clear-filtered beer. Either way a major limitation on bottled beer is guaranteeing an adequate shelf life, usually in the region of 6 to 9 months. In many cases this results from microbiological spoilage in others from oxygen pickup. Keeping levels of bacteria and wild yeast low is a skill well practiced by many brewers. Achieving low oxygen levels may require additional attention.

Filling by gravity into an open bottle will result in high levels of oxygen in the beer and an unstable product. Dark, high-alcohol beers are more likely to survive these conditions best but even so sales of such beers are best kept local. Even at this level consistency is likely to vary and while most bottles are adequate a significant proportion may become infected, oxidised and stale. To preserve your good reputation 100 percent of bottles should be in perfect condition.

A more guaranteed product is best obtained by counter pressure filling using an inert gas such as carbon dioxide or nitrogen. This process requires the bottle to be filled first with the gas and then with the beer. This keeps air away from the beer and reduces oxidation. The beer may be pressurised and carbonated before filling and should keep this pressure in the bottle so ensuring a fizz. Such a system cannot be rigged up just with a gas cylinder and requires more sophisticated equipment.

Simple bottling machines operate on a semi automatic basis where the bottles are positioned by hand, pressurised, filled on operation of a valve and removed for capping after pressure has been released. Given good cleaning, efficient seals and competent staff such small scale operations can bottle beer with low oxygen levels and a reasonable shelf life possibly stretching up to 12 months.

Such systems do have a production limit, usually in the range 200 to 500 per hour according to the number of filling heads and the skill of the operatives. Working at a reasonable pace this scale of production could bottle up to 40 barrels per week. Certainly a worthwhile addition to a small scale production but limited in satisfying national interest and supermarket demand. Moreover, labour costs will be high so limiting sales options.

More economic production requires a fully automatic system using a rotating head filler and conveying system for bottle transfer. Thousands of bottles may be filled per hour on such a system but at a high capital cost of at least £50,000 with additional costs for cappers and labellers. Such investment will produce a cheaper product but must have secure sales to return the investment.

An intermediate alternative is to look for contract bottling using specialist services. Here the brewer is responsible for the quality of beer and the bottler undertakes to package it with minimum alteration in quality. In some cases this offers the small producer a useful option between semi-automatic and full-scale bottling. A brand could be bottled initially on a small semi-automatic machine at the brewery and later by contract when sales become significant.

Whatever the choice of hardware bottling beer requires a number of prior considerations and treatments. It is easy to believe that fined cask ale is in peak condition to bottle. In fact bottle-conditioned beer is best bottled before final maturation so that some gravity remains to develop conditioning. Alternatively a fully attenuated beer may be primed with sugar although this has more potential to introduce infection. Moreover, the condition of yeast in bottle-conditioned beer can be critical. Suitable yeast levels may depend on the strain used and the production procedures. Judging suitable bottling times requires considerable skill and experience to avoid over carbonation. Spraying customers with a fine froth of beer is a poor way to introduce your brands.

Although yeast should cause no problems in filtered beer haze stability is a major requirement. This is typically achieved by precipitating protein and requires more attention to be given to the brewing process. Again additional skills will be required along with some dedicated equipment. Brewing for cask can be very different to brewing for bottle.


Written by Dr Keith Thomas
Brewlab Director

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