We promised (here) to be your guide in the world of craft beers. Well rinse the glasses, and let’s set sail!
First stop is fundamental: what is a beer, how is it produced?
In its contemporary version, the drink is composed of four fundamental ingredients:
- Barley malt (also other grains are used)
Four extremely simple elements, able under the guidance of a good brewmaster to give birth to a branching range of colors and sensations… How does then the magic happen? Which chemical and physical processes act on the mixture, thus determining its sensory features?
- Alchemy, cooking or science? Birth of a beer. -
The basic process, in brewing, is fermentation of the sugars contained in the grains into alcohol.
For this to happen, sugars must necessarily be available in forms simple enough to be ‘attacked’ by the yeasts: it is for this reason that the grains employed in brewing are malted.
Malting is a complex process contemplating the germination and follow dessiccation/roasting of the grains in dedicated chambers: when the barley (or other cereal’s) grain germinates, the enzymes developed during the vegetative activity break up the starch molecules to simpler sugars, able to be ‘digested’ by the yeasts.
Temperature and length of the dessiccation process, instead, apart from the sugars also effect the grains’ protein structure; originating caramelization, toasting and roasting phenomena which impact the final product – beer – in terms of aroma, sight, texture.
Malting is a process (almost) never taken care of by the brewery: it generally requires huge investments in terms of buildings and technology, so that most of the malt employed in beer making is produced by specific companies and subsequently sold to the breweries.
The brewing process then starts with the milling of malts. The milled grains are mixes in dedicated tuns with hot water (temperatures ranging from 30° C to 75° C, according to the characteristics a brewer might desire for the final product) and left to mash for a couple of hours: during this phase, proteins are broken down to aminoacids, sugars to elementary molecules.
Following step is the boiling: carried out basically to sterilize the wort and dissolve aromatic resins found in hops, which are added during this phase. The tannins found in hops, furthermore, clarify the wort; bonding with the suspended protein particles and having them precipitate to the bottom of the tun.
After the boiling worts enter a machine called whirlpool: it ‘centrifuges’ the must so to create, at the center of the tun, a… Whirlpool.The so-called ‘teacup effect’ generated by the whirlpool gathers the solid residues found in the wort (mostly hop fragments and cereal flakes) making them easily removable
After whirlpooling the wort is cooled, poured into fermenting tanks and inoculated with yeasts: then it will ferment at variable temperatures and time lengths, according to the desired type of fermentation. Fermentation can be ‘top’ or ‘bottom’ (we will deal with this further on in a dedicated post), and it is the ‘heart’ of the brewing process: that is, the thing able to transform a water and grains mixture into a complex and noble beverage.
Besides creating alcohol and CO2, fermentation harmonizes the wort; the incessant work carried out by yeasts creates most of a beer’s notable aromas.
Open-tun fermentation at Brasserie Cantillon, Bruxelles
When fermentation is complete, beer is matured, that is poured over and left to decantation: during maturation CO2 levels normalizes, the aroma rounds up as yeasts fall to the bottom of the tank to be successively eliminated.
The now-beer is then bottled, with or without small doses of sugars and yeasts aiming to obtain a second fermentation (bottle conditioning).