How do you turn a golden field of cereal grains into glorious, refreshing beer?
The SHORT answer is:
1. The farmer harvests the grains and hands them over to a Maltser.
2. The Maltser germinates, dries and/or roasts them and sends them to the brewer.
3. They are ground to form a grist and added to a mash tun with hot water. This is called mashing and
creates the “wort” (pronounced wert) or sugary brewing liquid.
4. It's then put into a kettle, hops and other ingredients are added. It boils away until the brewer is
satisfied.
5. It's drained, strained and cooled.
6. Yeast is added. It ferments.
7. The yeast is removed or filtered.
8. It's then aged and conditioned, sometimes filtered again and then bottled or put into casks or kegs.
9. Sometimes it is pasteurised, sometimes it isn't.
10. It then arrives in your glass, destined for your belly.
Here's the considerably longer answer...
Brewing at its finest is a spectacular and balanced display of a Brew Masters elegant selection and combination of myriad varieties of hops, roasted grains, malts, unmalted grains, yeast strains and water sources plus the considered application of heat, time and an artisan's eye.
The variables are infinite. The scope for creativity is enormous. The pathway to greatness can be treacherous, the rewards dazzling. For all of this, we give thanks, high praise and ask for another glass!
This information, although longer than the short answer, is still a rather simplified version of the processes involved. It's involved and it's sophisticated. Enjoy learning about some of the more common techniques – we did!
From Grain to Glass - The Brewing Process
From grain to glass, beer goes by many names before it is beer!
Malting
Malt is a term that is used for cereal grains that have undergone the malting process.
In essence it's the selection and collection of appropriate grains, steeped in water with intermittent aeration, germination of the grain, drying it and curing it on a kiln. Malting is usually undertaken by a Maltser, though some vertically integrated brewers grow and malt their own grains.
What the Maltser is trying to achieve and the brew master needs, is to transform and mobilise the grain's food reserves.
In simple terms we are after the internal food stores the seed would have used to grow into a plant and wake up the enzymes that control the process. We want a crushable outer husk with a soft, almost floury centre.
How to get that from a hard seed? It must be tricked into germinating and then quickly dried so that it stops growing and doesn't eat up its food cells – we need that for the beer. In more technical terms, the malting process stimulates the production of enzymes (alpha amylase and beta amylase) within the seed that soften its outer walls or husks and modifies its starches into a more soluble mass.
Malting turns a hard, almost indigestible seed into a plump and accessible, soluble form of starch. When cooked with water to produce the brewing liquid or wort (rhymes with bert), the enzymes get to work on the starches – supplying the brewer with the amino acids, polypeptides, sugars and essential metabolites for yeast growth – aka – the fuel to ferment, create beer and impart flavour, colour and consistency.
Not all cereal grains are created equal in brewing terms. They all have different yields and flavours. Brewers may use a single or a combination of grains and different levels of roasted malts, depending on their requirements. Around the world, barley, wheat, rice, corn, maize, rye, oats, triticale and sorghum are used.
Why most often barley?
Barley is particularly well suited to the brewing task and within this family of grains, some are better than others. In short however, barley's predominance as the most used grain in beer is based on its history, viability for cultivation, economics, availability and the following unique characteristics:
1. A barley seed has three outer protective layers - husk, pericarp and testa. This protects the seed through the stages of harvest, storage and malting.
2. The honeycomb microscopic shape of the husk makes for a good natural filter bed that is used to separate the wort or brewing liquid from the mash.
3. It has an insanely high starch yield, being 90 per cent carbohydrate – 80-85% of which is the grains food cell, exactly what the brewer is after.
4. When it has germinated or is green malt, it is extremely hardy and does not easily separate from its husk – keeping it intact for the brewer. (Malted wheat does not fair so well.)
5. It will only gelatinise at relatively low temperatures and therefore is less likely to clog up brewing vessels.
Flavour Descriptors for Malt Character (Source: Essays in Brewing Science).
When you are trying to discern the Malt character of your beer - here's a few taste sensations to get you thinking.
| Cereal |
Cookie, biscuit, hay, museli, pastry |
| Sweet |
Honey |
| Burnt |
Toast, roast |
Nutty (green)
|
Bean sprout, cauliflower, grassy, green pea, seaweed |
| Nutty (roast) |
Chestnut, peanut, walnut, Brazil nut |
| Sulfury |
Cooked vegetable, dimethylsulphide (DMS) |
| Harsh |
Acidic, sour, sharp |
| Toffee |
Vanilla |
| Caramel |
Cream soda |
| Coffee |
Espresso |
| Chocolate |
Dark Chocolate |
| Treacle |
Treacle Toffee |
| Smoky |
Bonfire, wood fire, peaty |
| Phenolic |
Spicy, medicinal, herbal |
| Fruity |
Fruit jam, banana, citrus, fruitcake |
| Bitter |
Quinine |
| Astringent |
Mouth puckering |
| Other |
Cardboard, earthy, damp paper |
| Linger |
Duration/intensity or aftertaste |
Milling the Malt - Preparation of the Grist
Milling of the Malt is required, so that the brewer can access the grain's internal soluble starches and use the husks and grits in the making and filtering of the wort or brewing liquid. In essence the idea behind milling is to create particles of just the right size so that water can dissolve them and the enzymes can attack them!
There are generally two types of milling undertaken by a brewery – wet or dry.
In a dry mill the Malt generally goes through a first set of rollers where the whole grain is crushed yet the husk stays relatively intact with the starches extruding a little. It then goes through a second set of rollers that then produce grits, cracked husks and flour. All brewers would be intimately aware of the milling technique and the grade they require their malt to be – from coarse to fine.
The second process is wet milling, whereby grains are steeped in water until they reach a particular saturation point and are then run through four sets of high speed rollers. The husks are split and the internal starches squeezed out in a slurry. This slurry is immediately mixed with water and added to a lauter tun (as distinct from a mash tun). The speed by which the malt must turn into mash sometimes causes this method to be seen as a combined process. This wet process is generally used in a decoction mashing process and the use of a lauter tun is used for its unique filtration system.
Brewing Water
It is patently obvious that water used for brewing must meet science based and vetted consumption standards set by the World Health Organisation. Not always so in the history of beer, but that's another story.
Beer is 90% water and has a profound effect on the final taste and appearance of beer. What you need to appreciate is that just as the brewer carefully selects and prepares the malt and grist, the same care is applied to the selection and preparation of the water.
Its PH, minerals and salts have differing outcomes that brewers try to counteract or accentuate and in some instances emulate. For example, brewer's wishing to make an English Pale Ale style will attempt to mimic the water used by the famous Burton-On-Trent brewers with the addition of salts (known in the trade as Burtonisation!) An important note for your further reading – brewing water is also referred to as liquor.
Mashing not Moshing
The cereal grains are malted, they have gone through the mill, the water has been checked and has the right molecular make up. Let's mash.
Mashing is the process where the malted and milled grains meet with hot water, in the right proportions, at the right temperatures for the right length of time, allowing the grain's enzymes to turn its starches into sugars that then combine with the water to make a mash that is then strained to create a sweet wort (rhymes with Burt) or brewing liquid. Phew...
The simplest method of mashing to explain is called Infusion Mash (or single temperature mashing) and is a little similar to making a pot of tea. It is and was more common in Britain (hence the pot of tea reference!)
Infusion Mashing, involves a single vessel called the Mash Tun, the base of which is covered with the water heated to 75 degrees Celsius (called striking or strike heat). The malt is then added, as is more water creating a thickish porridge. Temperature is closely controlled to 65 to 70C. Temperature is important – too high and the enzymes will give up and die, too low and the enzymes will fall asleep and the malt will turn into a gelatinous paste.
Before the advent of the thermometer it is said the brewer judged the water temperature based on the reflection of her face. As it turns out, water best reflects at 65 to 70C – perfect for a mash.
So this Mash, which is a thick heavy mass that is stirred by a mechanical mash mixer (Pity the poor medieval fellows that had to manually mix the mash with their wooden forks!) It is left to stand for about an hour and undergoes the glamorous chemical process of saccharification – the technical term for turning starches into sugars. When the brewers are satisfied that all of the starches have been turned to sugar, they raise the temperature and kill the enzymes.
It is ready for its next stage.
Sparge away and Mash Separation
If all the water required to make wort were added to the grist in one batch it would require a mash tun of pretty extraordinary size. It takes approximately 2.5 litres of water for every kilo of malt.
Water is added to the grain in two batches. The first batch is the mash water and is usualy half to a third of the water required. The secondi is the sparge water and generally makes up the balance.
The Mash needs to be drained from the Mash Tun and the liquid separated from the grist and husks of the spent malt. Fortunately the grains form a natural filter bed as they settle on the bottom of the Mash Tun. The Mash is drained through slats that are opened at the bottom and sprayed or sparged with more hot water. This ensures that none of the sugars are left behind and gives the Brewer a rich, sweet wort.
Mash Separation is an important element in any brewery and while sounding seemingly simple, it is critical on many levels. A brewer needs to get the most from the Malt and needs to manage the process effectively and free up the mash tun for the next run. The sparging process also helps kill remaining enzymes and stabilise the wort.
The Boil - put the kettle on
The drained mash, now known as sweet wort then arrives in the coppers or kettles, it is boiled and hops are added. The boil creates the bitter wort and fixes or stabilises its composition in preparation for fermentation.
Depending on the beer style, the main objectives at this point are:
• To sterilise the wort by boiling and destroy micro organisms that may be present. Just in case any malt related enzymatic activity has slipped through from the mashing and sparge process – the boil will stop them once and for all.
• Evaporate some water to concentrate the wort.
• Clear the wort by coagulating the proteins and tannins which will enable them to be filtered out as sediment in the trub or whirlpool separator.
• Extraction of resins and essential oils from the hops for their bittering, antibiotic and head/foam formation qualities.
• The colour of the wort may be intensified during the boil. Prolonged boiling can significantly darken the colour.
Originally, the wort was boiled in cast iron vessels that gave way to copper (hence the name copper or kettles). Stainless steel is also used today, although some argue that a copper kettle gives better colouring and you can't argue about how spectacular they look.
The hops are mostly added at the beginning, the middle and the end of the boil. Sugar and other adjuncts may also be added at this stage.
The bitter wort is now ready for its next phase.
Off the boil, methods of cooling
This hopped or bitter wort that has had the coagulated proteins and hop debris removed, needs to be cooled before yeast is introduced. This was originally done in shallow, open trays. An important element of this cooling process was the ‘cold break' where the wort becomes oxygenated and further settled out trub or unwanted particles. However, using open trays did leave the bitter wort susceptible to contamination and was problematic in summer. Other more capable systems and additional filtration has since been invented. Today, heat exchangers are generally used with a secondary filtration (particularly in the case of lagers).
The fervour of fermentation
The properties of yeast have been subject to heavy scrutiny over the years. The chemical reactions and microbial processes that take place are incredibly complex when seen through the lens of a microscope.
Traditional methods of beer fermentation were originally created through empirical observation and practice. Scandinavian Viking families’ most precious heirloom was the brewing stick they used to stir the wort that magically made the beer turn out. It really most likely held the yeast.
Today, yeast wrangling is driven by both creative influences dedicated to flavour profiles and a scientific drive for control, consistency and naturally, profits.
The brewing world is rightly obsessed with yeast. The major beer styles are classified along the lines of ales, lagers, lambics or others – primarily based on the type of yeast used.
Why is it so? Because yeast drives character and imparts flavour. In essence, it gives beer its identity. Prior to adding the yeast, the brewer just has a bitter wort that is looking for a purpose. It is the yeast that turns it into beer.
To grow, brewing yeast requires a carbohydrate source (the fermentable sugars in the wort), a nitrogen source (amino acid and peptides from the malt), vitamins, inorganic ions and water. The wort must be aerated.
After the bitter wort hits the fermentation tank the yeast must be pitched in (pitching being the trade term for the addition of yeast). The rate at which the yeast is pitched, its amount, timing and the temperature of the bitter wort are important considerations for the brewer.
After the yeast has been added, things get very quiet as the microscopic single cell organisms start budding and multiplying in preparation for the feast ahead. Nothing much seems to happen. A few hours later, with the yeast army ready and waiting, a few wisps of foam signal the beginning of the gluttony – primary fermentation.
The yeast begins its assault on the sugars and nutrients in the wort converting them to ethyl alcohol and creating carbon dioxide.
Yeast also produces:
* Esters - the compound responsible for the fruity notes in beer
* Phenols – create the spicy notes and a combination of the medicinal/chlorine qualities
* Ketones - Diacetyl which can give a butterscotch flavour but needs to be managed closely
to avoid a rancid flavour
* Fusel Alcohols – are heavier molecular alcohols. They give the sharp notes, but may also
be one of the responsible culprits for hangovers (the other being the drinker of course!)
If you are brewing ale, and therefore using the ale yeast strain, there will be an impressive display of thick, yeasty, puffy meringue on the top of the fermentation vessel. Lagers, due to their bottom fermentation are a little less impressive but equally hard working.
You will hear about batch fermentation, continuous process fermentation, primary and secondary fermentation. The word fermentation is derived from the Latin fevere – to boil. It most likely refers to the flocculated or clumped yeasts cells that appear to boil as it heaves itself to the surface during ale fermentation.
The fermenting yeast also produces quite a lot of heat and brewers use cooling jackets around the fermentation vessels to control the temperature. Over a few days, the yeast will have consumed most of the sugar. In fact, brewers seek out a particular gravity or sugar content from the process. The final product needs to have residual sugars for both body and flavour. When the brewer is happy with the gravity of the fermented bitter wort, it is cooled and the yeast is removed. The cooling allows more of the yeast particles to settle out of what is now called green beer.
Conditioning and maturation – beer becomes beer
Conditioning is the process of turning green beer (fermented bitter wort) into mature beer. Whilst conditioning is a less dramatic process than fermentation, it is an absolutely critical and technical component of the brewing process. It can also be expensive and the difference between success and failure in terms of taste.
After the hard work of primary fermentation, beer needs to rest. At this stage the brewer is looking to mature the beer’s flavour, reduce the rougher alcohols, stabilise it and minimise any dissolved oxygen. It may also be clarified.
There are many different conditioning and maturation processes available to the brewer that all have their own unique and profound effect on the final result. The beer may be filtered and then pasteurised, bottled and carbonated. The brewer may be producing real ale and decants the green beer, casks it and adds hops and sugar for a secondary fermentation - which also coincidentally carbonates the beer. The process is also known as cask conditioning. It may be partly filtered and bottle conditioned with the addition of further yeast and sugar.
The conditioning process for ales and lagers significantly differs. Lagers name is derived for its long conditioning process (Lager is German for store.) Many of the larger scale breweries today have developed processes to avoid this requirement whilst still maintaining a Lager profile. Lagered beers or more accurately, beers that undergo an accelerated lagering are generally pasteurised, are virtually free of yeast and fully attenuated. They can be produced very quickly. Ales generally go through a two to four week conditioning process, yet can be subjected to longer resting, depending on the brewer’s objectives – for example the cask conditioned and bottled conditioned ales can continue to mature for years.
BEERLIOGRAPHY
Lewis, M & Bamforth, C,. Essays in Brewing Science. California; Springer Science and Business Media. 2006.
Hornsey, I. Brewing. UK; Royal Society of Chemistry.1999.
Protz, Roger. The Taste of Beer. London; Weidenfeld and Nicholson, 1998
Hough, J.S, Briggs, D.E, & Stevens, R., Malting and Brewing Science. London; Chapman and Hall. 1971
Rabin, D, & Forget, C,. The Dictionary of Beer & Brewing. Michigan; Brewers Publications. 1998.
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