The Processes

The Hall Brewery
This 10 bbl (bbl stands for barrel which is equivalent of 36 UK gallons or 163.66 litres) brewery, situated in a converted stonemasonry/joinery shed at Thornbridge Hall was originally used by Marston Moor brewery in North Yorkshire until its installation at Thornbridge near the end of 2004. The brewhouse uses 20 barrel hot and cold liquor tanks and utilises a single temperature infusion mashing system. Our mash tun has a slotted false bottom and is sparged after the mash period is complete (usually 75-90 minutes), collected in a small underback (a vessel that acts as an intermediate between the mash tun and the kettle itself) and pumped into the kettle. The kettle has a gas fired internal coil and the wort is hopped and boiled for 75-90 minutes before being passed through a heat exchanger and aerated on its way to the fermenting vessels. Our very own strain of yeast is added and fermentation takes place over three to five days, after which the beer is chilled. The yeast is collected (for repitching) and the beer is transferred to a conditioning tank where maturation occurs prior to casking.

Riverside
Installed and commissioned in 2009, this is all about using the best technology we can to continue making great beer. Loads of research culminated in an Italian manufactured 30 bbl/50 hL (hL means hectolitre, which is a commonly used brewing term meaning 100 litres) brewhouse with one piece of
So now for the science!

Brewing begins with water. Our water supply is the same for both breweries which is extremely important in giving us a consistent beer character no matter where the beer has been brewed. The water supply to Derbyshire is relatively soft, which is very beneficial for brewing, allowing us to modify the water through the addition of a variety of mineral salts. This lets us emulate water from different areas of the world. We may want to go with London style water for a Porter, Dublin style for a dry stout and Burton style for a pale ale. Varying amounts of five different salts are used and these are Calcium Sulphate (gypsum), Calcium Chloride, Magnesium Sulphate (Epsom salt), Sodium Chloride (table salt) and Sodium Bicarbonate (baking soda).

What’s the point of using these salts? As I’m sure you’re aware, beer is mostly water, usually between 90 and 94%. Water is a great solvent and all of these brewing salts dissolve in water (to a greater or lesser degree) and undergo a process called dissociation. Water is a molecule that exhibits polarity, meaning that the hydrogen and oxygen molecules have charges. It is these charges that allow our brewing salts to break up into their ions. For example, if we were to dissolve sodium chloride in water, the positively charged sodium ions (Na+) would be attracted to the negatively charged oxygen ions (O2-) in the water and the negatively charged chloride ions (Cl-) would be attracted to the positively charged hydrogen ions (H+) in the water.

This is all fair and well, yet how does this help the brewer? The fact that these salts dissolve allows all of these ions to affect certain parts of the brewing process. Calcium is important during mashing. It boosts and stabilises enzyme activity during mashing (both by pH reduction and heat protection of enzymes), as well as aiding starch gelatinisation and lautering performance. It also binds with phosphate ions (from the malt) which facilitates a decrease in pH in the boiling of the wort, inhibits too much colour formation, aids the coagulation of proteins and effects bitterness extraction during boiling. It is also important in fermentation performance and the flocculation of yeast cells and helps prevent haze. A pretty important ion!

Magnesium also helps to lower the pH of the mash but more importantly, it is important as a cofactor for yeast during fermentation. It’s important to be aware that magnesium ions can contribute harsh bitterness to a beer though, so these salts are always used with caution!

Carbonate or bicarbonate ions are also very important in brewing. These play a major role with regard to the pH of the water. Remember that the enzymes that are present in the malted grains themselves all work at an optimum temperature and optimum pH, hence it is essential that these are balanced correctly. These ions tend to move the water more towards a high pH (alkaline) which works in the favour of dark beers, where the malts used often contain compounds that can be quite harsh or astringent. The ions help to balance out these acidic dark malt characters. However, in well-hopped beers, alkaline water tends to result in a rather intensely bitter beer. At Thornbridge we always take this into account, the biggest challenge is how to use salts in a dark, well-hopped beer!

Sodium affects the perceived flavour of the beer by enhancing its sweetness. Kind of weird when you think that we use salt on our food to increase its saltiness! The only thing is that you have to be careful when using too much of this in the presence of sulphate ions. Sulphates give crispness and dryness to the palate when used correctly, but can tend towards salty and harsh (and laxative!) if over-used. If you have too much of both sodium and sulphate ions in a beer you also get an unpleasant harshness, so again, it comes down to balance. Chlorides also give a rounded, full bodied beer and are beneficial when used in darker, sweeter beers. There are loads more ions that play minor roles in brewing, but I’m sure you want to learn a bit more about how we make the beer!