Brewers want to get to the starchy insides of the kernel, called the endosperm. Endosperm contains protein, minerals and nutrients, but most importantly, starch, which is a complex carbohydrate. We want the yeast to work with that.

The key of milling is that the access to the endosperm is easy and the husk remains intact enough to serve as a natural filter bed in the next stages.

Time and temperature are key. When malt and warm water mix, enzymes activate: starch is hydrolyzed by amylase enzyme to produce single sugars, maltose and maltotriose. The latter is devoured by yeast only when they consume the whole of maltose. Two most important enzymes are at work here: β-amylase has optimum activity at temperature 62°C whereas α-amylase has optimum activity at temperature 74°. This may sound complicated, but thanks to this knowledge the beermaker can manipulate the “fermentability” of the wort, which is the liquid left after filtration. If there is more maltose in wort, beer will be more dry, so it’s sufficient to keep the mash in temperatures close to 62°C — and we get dry beer. If on the other hand we’re after a fuller tasting beer, we need to mash in higher temperatures. In reality, to reach a perfect balance, brewers use mashing programmes, for example 30 mins in 62 degrees and 20 mins in 74.

When the mashing is complete, the brewer moves onto lautering, which is the process of separating the wort from the grain. The purpose is to remove sugars that may be trapped within the grain following the mash. Good balance is essential here as well: filter too fast and the sugar concentration in the wort will be too low. Filter too long, and tannins will be rinsed out, causing the beer taste fairly dry and ‘stemmy’. An experienced brewer knows where the perfect balance lies.

After filtration is done, the boiling stage starts. It has a number of goals:

Sterilisation
Killing all wild yeast, fungi and bacteria, which there is a lot of in the original product, i.e. malt.

Hot break
Ensuring clarity of the beer

Removing DMS precursors
DMS (Dimethyl Sulfide) is a byproduct of mashing and fermentation, has the aroma of cooked vegetables and is highly unwanted in the final product. An experienced brewer knows exactly how long to boil the “veggies” for to evaporate.

Wort hopping
The two main things the brewer loves his hops for are: alpha-acids and aromatic oils. Alpha-acids give bitterness, oils give aroma. The aromatic oils are insoluble and evaporate during the boil at 50 degrees. The challenge is that the alpha acids dissolve at above 85°C, so again, a fine balance is necessary to get the best out of the two. It is accomplished by adding hops in batches, at the beginning (to dissolve as many apha acids as possible) and then at the very end of the boiling (to lose as little aromatic oils as possible). There are naturally hops types with more acid content and those with more oils content and the brewer knows this from his hops farmer friend – how else?

When the boiling is over, the wort needs to be cooled down immediately, because as transient as DMS is, it has the ability to re-bond fairly quickly — and the beer will end up smelling of sauerkraut or cauliflower. Fast cooling is a necessity also because we want the yeast to take over the wort rapidly, swiftly start the multiplication orgy and move on to the sugar feast. For low fermentation beers we cool to 10-12°C, for high fermentation – to 17-21°C.

Of course, all the stages above are super important, but fermentation is crucial. Swift, lively, efficient, healthy, no downtime. Without it there’s no beer. You can prepare an amazing wort but if you screw up the fermentation, the beer will be undrinkable. And to the contrary, one can make a lot of mistakes when preparing the wort but excel at the fermentation and the beer will end up fine.
In a nutshell: yeast consumes alcohol, produce carbon dioxide and ethanol. The variables here are:
• temperature: the lower the temperature, the slower the fermentation — but also “cleaner”, without the yeast aromas. The higher the temperature, the faster the fermentation, and the aromas of a bubble gum, pear, bananas will be more prominent. If that’s what the brewers are after, fine, but usually it’s avoided as the aromas are quite artificial.
• pressure: fermenting without pressure will result in a clearer beer, but you will lose quite a lot of aromas. Fermenting with pressure is quicker and keeps more aromas, but on the other hand, you can end up with some unwanted ones, such as sulphur compounds.
There are other factors at play, such as wort’s oxidation level, the moment when you change the temperature and pressure, the moment of separating beer and yeast etc. Suffice to say, fermentation is the brewer’s best kept secret.

After the fermentation is over, hops are thrown into the tank. As you already know, they will not add any bitterness, only the aroma. Here is one more opportunity for the brewer to show off his expertise: a skillfully composed hops composition and a perfect squeeze out of the aromatic oils.

This is not easy from a technical point of view, as after fermentation is done, beer is still quite vulnerable and by introducing air you risk alcohol breaking down into acetaldehyde. For the brewer this is an absolute nightmare: a beer tasting of green, sour apples.

A super important stage. It has to be impeccably clean (just like everything at a brewery), completely without exposure to air (see above re aldehyde) and if there is pasteurisation, it has to at a very low level, so that the aroma of the hops isn’t ruined.

This stage is critical. One can make a fantastic beer, have it bottled perfectly, only to wreck it completely in a truck: during summer heat or winter cold. All the hard work for nothing. Beer can’t handle temperatures below 1°C and above 18°C, and it hates sudden temperature changes. It won’t tolerate direct sun exposition and long shelf life, it likes to be drunk fresh. As you can see, efficient distribution given such demands is a piece of cake, huh?