Process

Once the malts have been selected for a giv en brew they are milled. This produces a fairly course grist in which the husks are left substantially intact while the rest becomes a v ery coarse powder. We then mix this grist with hot water in a traditional infusion mash tun. The volume and temperature of the hot water are carefully controlled to produce a thick porridge at a temperature of over 65°C. As the vessel is insulated this temperature is maintained during a stand of about one hour. Under these conditions the enzymes in the malt start to attack and so degrade the starch, there is also some breakdown of the protein materials. This produces what is called sweet wort. The mash tun has a slotted base which acts like a sieve. The husk material is then used as a filter bed through which the solution of sugars is separated from the remaining grain solids. In order to separate all the sweet wort from the undegraded material (spent grains) more hot water is sprayed over the surface of the mash via the spargearms.

The wort is transferred into a large vessel known as a kettle or copper (usually now made of stainless steel). Here it is boiled together with the hops. The boiling serves a number of functions including:

• Extraction of bittering materials and of aroma components from the hops
• Concentration of the wort, driving off unwanted flavour compounds
• Inactivating any enzymes that may have survived mashing
• Sterilizing the wort (hops also help in this as they contain antimicrobial compounds)
• Coagulation of protein and tannin material to form an insoluble complex called trub

As the hops lose their essential oils during boiling additional hops are added towards the end of the boil. These are sometimes known as the aroma hops. We use whole hops and so can use the hops themselves to form a filter bed through which the precipitated material can be separated from the wort solution.

The wort is now cooled via a heat exchanger from about 101°C to 20°C and oxygenated during transfer to the fermenting vessel. The water used to cool the beer is heated up during the process; this is recovered and used for the subsequent brew. Yeast is now added (pitched) to the cooled oxygenated wort and allowed to ferment. Fermentation is mainly concerned with the conversion of sugars into alcohol, the rate at which this occurs depends on temperature and the amount of yeast pitched. However there is more to brewing than simply producing alcohol. It is about producing a subtle mix of flavours the balance of which will depend on the yeast strain. This is why we look after our yeast!

The other by product of fermentation is carbon dioxide some of which goes into solution and the rest is given off as a gas. The carbon dioxide in solution is what gives beer its ‘condition’. Our cask beers contain only carbon dioxide produced from the yeast. Our bottled beers are carbonated but to a lesser extent (about a third less) than most bottled or canned beers. Once the beer has fermented it is either run into casks for despatch to the pubs, or into bottles for the supermarkets and pubs. With our cask conditioned beers finings are added to the cask which is why it needs to be allowed to settle (usually for 24hrs) before serving.