Where the hard work begins. The malts are introduced into the Mash Tun along with hot water (at around 70’C) where the malts release colour, flavour and most importantly their natural starches are converted to sugars. A Pale Ale will have (not surprisingly) very light malts, whereas a stout or a porter will have a much darker malt bill. After around 2 hours the Wort (the resulting sugary liquid) is ran off from the now spent malt and transferred over to the kettle.
Commercial brewers do their first bit of cheating at this part of the process. Rather than using the very best malts they can find they substitute malts for rice, wheat or corn which is much cheaper than malt. They can still extract the necessary sugars to create beer, but the resulting product will lack body and flavour and be very obviously inferior.
The Boil can take from 1 hour up to 12 in some very extreme cases but more normally takes around 1.5 hours. It is at this stage that hops are added to the wort to start to balance the extreme sweetness of the sugary wort. Traditionally hops were added to help preserve the beer (as they are a natural preservative) but they have developed into an integral part of the flavour and body of the beer.
Hops can be added at any point through the boil depending on what the brewer is trying to achieve. Hops added early in the boil will steep for much longer and release far more of their alpha acids (the reason hops impart bitterness) into the wort. Added later in the boil the hop will impart less bitterness and more flavour and aroma.
The boil also acts as a sterilisation process for the beer. Afterwards the beer is cooled down to around 18’C and transferred over to a fermentation vessel.
The Fermentation Vessel
This is where the magic really starts to happen. The yeast is introduced into the newly boiled wort, where the little yeastie monsters begin to hungrily devour the sugars in the liquid. Over the course of around 7 to 14 days the yeast will gorge themselves, multiplying, creating alcohol and carbon dioxide. The beers final alcohol content is governed by the levels of sugar present in the beer when transferred from the mash tun right back at the start of the process. The higher the sugar content, the more work the yeast can do, and the higher final abv. There are various types of sugar present in the wort however and the yeast is only able to access some of them, hence why sugars can be left in the beer to create body and sweetness.
There are various different types of yeast and most of them do their work at the top of the FV. If you look into a FV as the fermentation process is happening you will see a maelstrom of activity, with a heavy white foam being produced. During a heavy fermentation it has been known for the foam to overflow the FV and spill onto the brewery floor. There is however an exception to this, and that is lager yeast. Lager yeast operates at the bottom of the FV, so if you were to look into the FV you would see very little activity. Ale yeast is known as ‘top fermenting’ and lager yeast as ‘bottom fermenting’. Imaginative names indeed.
The Conditioning Tank
Once the fermentation process has finished the yeast will be removed from the beer and the beer will be transferred to a Conditioning tank where the final part of the production process will take place. The beer will be slowly cooled down to around 0’C over the course of around a week and kept there for usually around 2 weeks, though this number can vary hugely from brewery to brewery, and can in the case of lager be extended up to 6 months (the word Lager is actually German for ‘cold storage’). It is during this period that all the flavours that have been lovingly imparted into the beer are able to blend and fuse together, creating depth and body, providing that wonderfully balanced product that will end in our glass. The cold storage process also allows brewers to stabilise the beer and extend the eventual shelf life of the product without having to add horrible chemical preservatives or pasteurising the beer.
This is a hot topic in the world of craft beer and is one of the steps of the process that so differentiates commercial, large scale breweries from craft breweries. The final product in the conditioning tank is the beer that the brewer has so lovingly created, however this product needs to be cleansed and all the final larger bits of yeast and hop left over from the kettle and FV need removed. Large breweries producing tasteless products will filter the hell out of their beer, forcing the product through a filter with the tiniest holes, stripping away all the body and a lot of the flavour. A craft brewer wouldn’t dream of doing this after all the hard work put in creating that flavour, so in most cases will simply filter the beer through a far less dense filter. This is still a step too far for some though. There are various other methods including the centrifuge which essentially is a very high powered whirlpool which forces larger materials to the side allowing the clearer liquid to pass through.