Our Brewery - Science or Art?
Not quite the work of an alchemist, but brewing is a centuries old craft. Yes, it is based on science but the difference between a pint of beer and a great pint of beer is the quality of the ingredients and the skill of the brewer.
At The Inveralmond Brewery, our brewers produce great beer.
The Ingredients Of Good Brewing - Water
The water content in any beer is more than 90% and consequently plays a major role in the final product. However, even though water is water to most people, nothing could be further from the truth as far a beer brewing water is concerned.
The best water for brewing beer and the most prized is from natural sources which contain elements not found in other water sources. Two of the major elements are calcium and magnesium: they are crucial when it comes to making a fine beer. Not only do they add a desirable mouth feel of their own, but they also aid many of the biochemical processes taking place during brewing.
For centuries Perthshire has been renowned for its pure waters. Several of the bottled waters available today throughout the world are sourced from Perthshire's natural mineral springs. Little wonder then that so many famed whiskies were produced from these pure Perthshire waters, the same waters that provide the essential ingredient to all our Inveralmond beers.
The Ingredients Of Good Brewing - Malt
Malt is shorthand for barley that has undergone a process called malting. Malted barley is the main cereal used in brewing beer and the only one that falls within the German purity laws - the Rheinheitsgebot - under which most of the famous beer producing country's beer is made, and to which brewers in some other parts of Europe, such as the Czech Republic also adhere to.
The principal role of malted barley is as a source of sugars that provide the potential alcohol content of the beer achieved through the fermentation process. But the type of malt used can also affect the appearance and flavour of the final product.
A pale malt tends to produces a relatively lighter beer in flavour and colour, while a heavily-kilned malt will produce darker, richer flavoured beers, though of course there are many other aspects of the brewer's art that will affect this.
The Ingredients Of Good Brewing - Hops
Hops are essential to brewing, if a relatively minor ingredient in terms of weight used. Hops come in many different varieties, and can be added at different stages of the brewing process to allow us to impart both flavour and aroma. Hops are the cultivated flower of the Humulus lupulus plant, a close relative of which is marijuana!
We are proud to say we use whole hops in the brewery, as can be seen in the photograph here.
The Ingredients Of Good Brewing - Yeast
Brewers classify yeasts as top-fermenting and bottom-fermenting. This distinction was introduced by the Dane Emil Christian Hansen.
Top-fermenting yeasts (so-called because they float to the top of the beer) can produce higher alcohol concentrations and prefer higher temperatures. An example is Saccharomyces cerevisiae, known to brewers as ale yeast. They produce fruitier, sweeter, ale-type beers.
Bottom-fermenting yeasts produce fewer of the esters that cause the fruity taste in ale, leaving a crisper taste, and work well at low temperatures. An example of bottom fermenting yeast is Saccharomyces uvarum, formerly known as Saccharomyces carlsbergensis. They are used in producing lager-type beers.
Brewers of Bavarian-style wheat beers often use varieties of Torulaspora delbrueckii, which contribute to the distinctive flavour profile.
To ensure purity of strain, a 'clean' sample of the yeast is stored in a laboratory environment at refrigerated temperature. After a certain number of fermentation cycles, a full scale propagation is produced from this laboratory sample. Typically, it is grown up in about three or four stages using sterile brewing wort and oxygen.
The Essentials Of Good Brewing - Milling
The process begins with the malted barley being lightly crushed into a coarse powder called grist. At this stage, other cereals (usually called adjuncts) - including flaked maize, unmalted barley and wheat can be introduced, if required by the brewer's recipe to produce particular characteristics of flavour or colour or appearance. Darker malts are used for stouts.
The Essentials Of Good Brewing - Mashing
The grist is transferred to a large vessel called a mash tun, where it is mashed (or mixed) with hot water (similar to the process of making a cup of tea).
Over the course of a couple of hours, starch in the grains is converted to sugars by the action of natural enzymes in the malt. The natural sugars in the malt dissolve in the water (brewers always call this water liquor), and eventually a sweet brown liquid is formed.
The liquid is allowed to run out, strained through the malt husks, supported by the false bottom of the mash tun. Hot liquor (actually, water) is gently sprayed ('sparged') over the malt grains to extract all the goodness. This 'sweet wort' collects in a small vessel called the underback, from where it is transferred to the boiling vessels.
The Essentials Of Good Brewing - Boiling
The wort, as it is called, is then boiled vigorously with hops in these vessels, known as coppers. This extracts flavours and bitterness from the hops, coagulates unwanted protein and phenolic material ('trub') and kills any contaminant micro-organisms. Some 'late hops' can be added at the end of the boil for extra aroma and taste
The Essentials Of Good Brewing - Fermentation
The next stage is fermentation, the most critical process of all.
The hopped wort is cooled and run into fermentation vessels. Pure, natural yeast is added (or 'pitched'), and it begins to vigorously convert the natural sugars into alcohol, carbon dioxide and a range of subtle flavours.
Yeast strains are jealously guarded by brewers because of its importance in determining the brand's characteristics. Fermentation can take anything from a few days to several weeks depending on the style of beer.
Historically, all British ales and stouts were fermented with yeast that rose to the top of the beer, and in many cases this method is still used. These top fermenting beers develop cloud like, foaming heads. When the yeast has done its job, the head settles into a thick, creamy crust, protecting the beer from air in open fermentation vessels.
Lagers are fermented with a different type of yeast which works at colder temperatures, and which sinks to the bottom of the fermenting vessel. Known as bottom fermentation, to ensure hygienic conditions, enclosed fermenters are used with a conical base, in which the yeast settles into the base.
These days many ales are also fermented in closed conical fermenters.
The Essentials Of Good Brewing - Conditioning and Racking
Finally, the 'green' beer is racked off the sediment into a conditioning vessel ('CV') where it matures and there is further settling of yeast. Before a beer leaves the brewery it must be conditioned. The conditioning process differs according to how the beer is to leave the brewery.
For cask conditioned beers (real or cask ales), the beer can go directly into the cask, barrel or bottle. More hops may be added to the cask (dry hopping) for extra aroma. Finings (traditionally made from the swim bladders of certain fish) are added which bind the materials responsible for haze and sink to the bottom, clarifying the beer.
The yeast in the beer is still active, and the beer will undergo a secondary fermentation in the cask, normally in the cellar of a pub. Cask conditioned beer is a delicate product and, just like the beer undergoing fermentation in the brewery, it is vulnerable to attack from all kinds of contamination by wild yeasts and other micro-biological organisms.
Other beers are brought to condition in the brewery, some are fined and filtered and some are pasteurised to guard against deterioration from microbes. Sometimes known as 'bright beer', they reach the consumer in casks, kegs, bottles or cans. For lagers there is a longer period of conditioning in the brewery at low temperature. The word lager comes from the German word lagern - to store at a cold temperature.