The mash tun is filled with hot liquor (water) at a strike heat of approximately 73°C. The malt is then poured into the mash tun and mixed to a porridge like consistency with a temperature of 65 – 68°C. The Mash is then covered and left to stand for 90 minutes. During this time natural enzymes contained within the malt convert the malt starch into sugars.
As well as providing a source of fermentable sugars malt is used to provide colour and flavour. A wide variety of different malts are available and the ones commonly used at Pictish Brewing Company include Maris Otter pale ale malt, wheat malt, crystal malt, chocolate malt, roast barley, amber malt and lager malt.
After the mash has been left to stand the sweet wort is pumped into the copper spraying the top of the mash bed with hot liquor at a temperature of 78 – 80°C (sparging). This ensures that most of the sugars are extracted from the malt.
As the sweet wort is collected in the copper hop flowers are added and it is heated until boiling. This first batch of hops are boiled for one hour and provide the bitterness to the beer. Five minutes from the end of the boil a second batch of hops is added which provide aroma and flavour to the beer. Hop varieties used include Brewers Gold, Cascade, Fuggles, Goldings, Bramling Cross and Saaz. After the wort has been boiling for an hour the heater elements are turned off and the copper is left to stand for ten minutes. The wort is then cooled to between 18 and 20°C in a heat exchanger and pumped into the fermentation vessel. This process generates hot water which is recovered into the hot liquor tank ready for the next brew.
Once in the fermenter the yeast is added (pitched) and left to ferment. This usually takes between three and four days but can be up to a week for stronger beers. During this time the temperature is automatically controlled to a maximum of 23°C. Once the beer reaches the correct strength the yeast is skimmed off the top of the beer and the fermenter is cooled to 8 – 10°C and held at this temperature for three days. This cooling stops the fermentation and allows most of the yeast suspended in the beer to settle out. The beer is then racked into cask, finings added and stored ready for delivery.