Talk to some brewers and you may come away with the impression that making beer is a cross between art and alchemy. Fortunately, David Cook from the University of Nottingham is here to tell us all about The Research Behind Your Pint.
Making beer is a relatively straightforward process, you only need four ingredients - malt, hops, water and yeast. First the malt is mashed, this is what gives a brewery that distinctive smell and this porridgey mixture turns the starch in the malt into sugar. This sugary liquid is then filtered to remove any solids and the resulting liquid is called wort. The wort is then boiled and the hops are added. Back in the Middle Ages, this boiling process meant that beer was actually safer to drink than water. Then it's filtered again to remove any more pesky solids. This remaining liquid is then chilled and aerated, which allows the yeast to grow. The yeast turns the sugar into alcohol and this fermentation takes place on massive scales in modern breweries with fermenters being as large as 4,000 hectolitres. Fermentation takes around a week. The beer is then filtered again to improve its shelf life and CO2 may be added to carbonate it.
These days, most breweries use a high gravity brewing process as this is the most efficient way of making beer. Using this process, a beer that ends up around 4% ABV probably starts at around 8% and is then diluted down to 4%. And you thought it was the landlord that was watering down your pints!
Within David's team, there are a number of groups looking at different projects to try and improve the brewing process. There are crop scientists looking at the regulation of germination of the barley. It has to break dormancy to malt but if this happens on the ear, it's too soon. Ideally, you want it dormant for around two weeks after harvest. There are also parallel groups looking at how pesticides and fungicides effect the barley.
The process of removing the malt from the barley is inefficient in terms of both energy and water usage. However, it is so simple to do that you could actually do it at home. You take the barley and stick in a bucket of water, which you then put in the corner of the room. You have to keep it moist and maintain it at room temperature, then bosh it in the oven at 80oC and Bob's your uncle, you've got malt. In a modern brewery, it takes 24 hours to dry 200 tonnes of barley.
In some beers an adjunct is added at the boiling stage, which is something that isn't barley but that is a source of sugar for the yeast. For example, Budweiser, is made with around 50% rice. However, when barley is germinated, it creates enzymes that break down its own cells. This is a really efficient way of converting starch into sugar and could prove to be better than adding adjuncts.
The other problem that barley has is that around 20% of the barley going into mash is insoluble. At the moment most of this is fed to cattle but there really isn't very much money in it and while people have tried to use this left over barley to try and make both bricks and Tarmac, there must be a way of making more money from it.
One of the other things that David's team is looking at is yeast. Yeast is responsible for the main characteristics of beer and different yeasts are used in ale and lager. In fact, there are only two different lager yeasts in the world. Unlike distillers, brewers use their yeast many times - a lager yeast is normally used around six times but can be used up to 20 while some real ale brewers re-culture the same yeast forever. In between brews, yeast is frozen at -80oC so that it can re-propagate in the brewing process.
One of the issues that yeast can have is premature yeast flocculation. This is where the yeast comes out of the solution while there are still sugars in wort. It happens intermittently and no-one knows when it will strike but it is believed to be linked to the quality of the barley. Flocculation is usually the remit of isinglass finings, which are extracted from the swim bladders of fish and are a very pure form of collagen.
The bitterness of beer is measured in Bitterness Units (BU). A lager such as Budweiser would be around 8BU, while a UK bitter is 35BU. It is the hops that give a beer its bitterness and so something really hoppy, such as an IPA could be as high as 50BU. In IPAs, the hops act as a preservative but the shelf life for most beers is 9 months and beer only stays properly fresh at 4oC.
One of the other things that David and his team are looking at is consistency. While wine makers make a positive out of the variability of their product with regard to harvest years, brewers want their beers to taste the same every time. Of course inconsistencies can creep into any element of the process all the way through to the quality of the dispense and what they clean the line with and how often.
40 years ago the best brewing lab was at Bass in Burton-upon-Trent but these days manufacturers don't maintain experts in-house all of the time. The complexity of the science, the equipment needed and the number of scientist mean that most breweries will partner with universities such as Nottingham in order to do research, which is where David comes in.
SciBar returns to the Vat & Fiddle at 7:30 on the 26th of July
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