Making Beer at Old Hall Brewery
Crystal and coloured malts
Beer is made from crushed malted grain, usually barley, which is first soaked in hot liquor (water), in a vessel called a Mash Tun, to remove soluble maltose. Different barley malts are used for our different beers. Our bitters are made from predominantly from Maris Otter Pale Ale malt and lager malt.
The flavour and colour of beers can be changed by varying the mix of other malt used, including the addition of crystallised roast malts and other cereals. These also influence the head of the beer when it is finally served.
The resulting solution of liquor and maltose is known as Wort and, in order to sterilise it, this is boiled for at least an hour in a vessel called a Copper or Kettle.
Most English beers are flavoured with hops to bitter them. However, Milds and some Stouts contain relatively lower levels of hop flavour, allowing the malt flavours to dominate the palate. Hops contain small oil producing glands in the base of each flower and small amounts of the oils from these can greatly affect the flavour. Varieties of hop that are very high in lupulin oils have nowadays been bred by plant breeders. Prior to the introduction of hops from mainland Europe in the early 16th century other herbs were used. Some brewers still make recipes which use wild herbs such as bog myrtle.
Cascade american aroma hops are added to the copper.
Towards the end of the boil, further hops can be added and this will determine the final aroma of the beer. Often a different variety of hop is chosen for its ability to impart a particular spicy, flowery or fruity aroma to a beer.
On leaving the copper the wort is pumped through a plate heat exchanger to cool it down to a temperature suitable for pitching the yeast. At Old Hall Brewery we cool beers that are top fermented to about 19 degrees C and bottom fermenting pilsners and bocks to about 12 degrees C.
At Old Hall Brewery we are fortunate to have purpose-made ale fermenters and also two lager fermenters. The difference lies in their shape and the temperature of the room in which they are housed.
Ales typically ferment in temperatures of 18 – 23 degrees C, using wider fermenters which allow the top-living yeast to form a yeast head on top of the fermentation.
By contrast, Lagers and Pilsners ferment at temperatures of 9 – 14 degrees C and are more suited to fermenters that are cylindro-conical in shape, allowing the bottom-living yeast strains to mass in the cone of the fermenter.
Lager fermenters in conditioning/ cool fermentation room
At Old Hall Brewery our lager fermenters are able to be wheeled into the chilled conditioning room, which minimises the amount of cooling required to maintain the low temperature of the fermentation.
At this point the amount of malt sugars dissolved into wort is measured by taking a reading using a Saccharometer to show the density of the wort at the start of the fermentation process. This is usually called the “OG” or “original gravity”.
Once all the wort is in the fermenter the chosen yeast type is mixed with a small amount of the wort and pitched into the fermenter. The wort is often roused at this point to ensure there is an adequate oxygen content to support the yeast’s growth.
Over a period of 2 – 21 days the yeast will convert most of the sugar to heat, carbon dioxide and alcohol. Brewers are able to calculate the strength of wort required to ferment a beer by using expected conversion rates – typically 12.9% of sugars in ale of up to 4.8 % ABV will convert to alcohol.
The gradual reduction in sugar is checked by taking Saccharometer readings on samples of the beer throughout the fermentation process.
The amount of sugars that the Brewer leaves in the beer will determine the sweetness of the final product.
Testing the OG of the wort with a saccharometer
Once the desired alcohol level is reached, the fermentation process is halted by cooling the fermenter and skimming off the yeast - from the top of a typical ale or from the bottom of a lager fermentation.
At this stage the beer can be transferred directly from the fermenter into casks, or it can be held in bulk vessels known as conditioning tanks.
In either case, the remaining yeast will slowly continue the fermentation process and will cause carbon dioxide to build up in the beer. This is described by Brewers as “conditioning”.
Beer is prone to a lack of clarity and there are three processes usually used to ensure that the final product is clear.
The first is when a special derivative of collagen is added to the wort whilst in the copper. This precipitates on transfer to the fermenter, taking with it a great deal of debris and loose protein from the grain which Brewers call “trub”.
The second and third stages take place both before, and at the point when, the beer is put into casks. A complex molecule, in the form of an auxiliary finings, is first added to the beer to increase the molecular charge of the yeast, thereby increasing it’s attraction to the Isinglass. Lastly, an Isinglass Finings is added which allows for the final clearing of the beer to take place in the cask after it has been delivered to the pub cellar.
Traditionally, brewers measure beer in Brewer’s Barrels which are 36 gallons (164 litres).
Firkins in distinctive Cumbrian Legendary Ales colours.
Most beer is sold in firkins which, at 9 gallons, are one quarter of a Barrel.
However, 18 gallon and 10 gallon casks are also still used, as are pins which measure 4.5 gallons.
