Our process

Produced by hand in the brewery’s steam copper, our ingenuity and passion transform the finest local malts and the best British hops into consistently high quality beers, whilst minimising impact on the environment.

  1. 1. Malting

    The brewery is very fortunate in having an abundant supply of locally grown and locally malted barley. Quite often the fields close to Box Steam Brewery are planted with barley, which is a fine sight. We use only traditional, floor malted Maris Otter barley, largely sourced from Warminster. Warminster Maltings operate one of the few remaining traditional floor maltings. Here, barley is steeped in water to trigger the natural germination of the grain before being loaded onto a floor where the maltster carefully turns the grain by hand to ensure even germination.

  2. 2. Milling

    After a relatively short period, growth in the ‘green malt’ is arrested by kilning. Depending on temperature, moisture and time, and with the skill and care of the maltster, a large range of flavours and colours can be achieved, from the grassy notes of lightly kilned malts, biscuit notes in pale ale malts through to burnt, acrid and very dark roasted malts.Thanks to the malting process, malted barley is very easily ground. At the brewery, prior to brewing, the malt is milled in a two roll mill to produce a coarsely ground mixture called the ‘grist’. This is stored in our grist hopper.

  3. 3. Mashing

    The Mash Tun is pre-heated using surging steam from our steam boiler. This is done to ensure a consistent mash temperature at 65 degrees is achieved. In the Mash Tun hot liquor (water with added minerals) and grist are gently mixed to form the ‘goods’ or ‘mash’. Once the mash tun is filled, it is left for an hour or so to enable the natural process to continue. Enzymes from the barley break down complex starch molecules into simple sugars. Later, these sugars will be consumed by the yeast to produce alcohol. The mash produces a liquid called ‘sweet wort’. More hot liquor is sprinkled over the grain to extract the goodness, a process called ‘sparging.’ After the mash has stood for the hour, the sweet wort is run off into a ‘whirlpool underback’. This ensures that only clear wort is transferred to the copper, to make the best ale.

  4. 4. Steaming & Boiling

    There are four steam jackets on the copper and these are switched on as it fills. The steam boilers are used to drive the steam jackets on the copper. The copper is usually steaming as the running off from the underback finishes. Steam boiling avoids any charring of the delicate hops, which can happen with other methods of direct heating. The temperature of steam can also be controlled much more precisely. The first hops are added at this stage. The wort is at boiling point and vigorously boiled for an hour or so. During this time natural resins are extracted from the hops and their bitterness is released. Second and late hop additions impart more flavour and aroma. The process also removes proteins which would otherwise cause a haze in the beer. A seaweed derivative called Irish Moss is added to assist this process. Boiling also makes the wort sterile.

  5. 5. Fermenting

    The boiled wort is cooled to 18C using a heat exchanger and collected in our fermenting vessel. Cold liquor is used to cool the wort, gets heated in the exchanger and transferred into the hot liquor tanks ready for the next day’s brew. Yeast is added to the fermenter to begin fermentation. The yeast consumes the sugar from the malt to produce alcohol and carbon dioxide. Heat is given off as the yeast grows and the temperature of the brew is carefully controlled to allow flavours to develop slowly. After several days, when the yeast has produced the correct level of alcohol, the temperature is brought down to 10C.

  6. 6. Conditioning

    Our beer is now either racked off into casks and left to condition for several days in a cold store, or it is chilled to 0C for bottling. Cask beer or ‘real ale’ carries a portion of yeast in it. Residual sugar from the fermentation is slowly consumed by this yeast in cask to produce natural carbonation or ‘condition’. When the beer is racked, isinglass finings made from the swim bladders of fish is added to ‘flocculate’ and ‘precipitate’ the yeast which settles as ‘lees’ in the belly of the cask after a 24-hour stand in the pub.

  7. 7. Serving

    Our cask ales are served perfectly in great pubs across the country, hand-pumped from cool cellars to proper glasses by skilled bar staff. All you have to do is order and enjoy! To get the most from a bottle of Box, serve it at 13C (chill it in the fridge, but take it out 20 minutes before serving). Always use a clean, straight-sided pint glass and pour in one go. Hold at a 45° angle. Pour the beer gently, aiming for the middle of the slope of the glass. Halfway, bring the glass to a 90° angle and continue to pour in the middle of the glass. This will create the perfect head of about 1 cm. Lovely.

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