Brewing methods
Encyclopedia
Brewing
is the production of beer
through steeping a starch source (commonly cereal grains) in water and then fermenting
with yeast. Brewing has taken place since
around the 6th millennium BC, and archeological evidence suggests that this technique was used in ancient Egypt
. Descriptions of various beer recipes can be found in Sumer
ian writings, some of the oldest known writing of any sort. Brewing is done in a brewery
by a brewer, and the brewing industry is part of most western economies.
There are several brewing methods, such as barrel aging, double dropping, and the Yorkshire Squares and Burton Union systems.
s are sometimes aged in barrel
s to achieve a variety of effects in the final product. Sour beers such as Lambic
s are aged in wood (usually oak) barrels similar to those used to ferment wine, where a secondary fermentation takes place, usually including microflora other than Saccharomyces cerevisiae
. Other beers are aged in barrels which were previously used for maturing spirits. Porters
and stout
s are sometimes aged in bourbon
barrels. Goose Island
's Bourbon County Stout was one of the first bourbon barrel-aged beers in the U.S., but the method has now spread to other companies, who have also experimented with aging other styles of beer in bourbon barrels (Allagash Brewing Company
, for example, makes a tripel
aged in used Jim Beam
barrels.)
By the early twenty-first century, the method of aging beer in used wine barrels had expanded beyond lambic beers to include saison
, barleywine, and blonde ale. Commonly, the barrels used for this had previously aged red wine (particularly cabernet sauvignon
, merlot
, and pinot noir
).
The Captain Lawrence Brewing Company
is known for producing several beers aged in a variety of barrels. Notably their Smoke from the Oak Series are Porters
that have been aged in either merlot, bourbon, or rum
barrels. Their Golden Delicious is a tripel
that has been aged in barrels previously containing Apple Brandy
or AppleJack
. Rosso e Marrone' is an Oud bruin
aged in wine barrels infected with Brettanomyces
, a species of wild yeast that lends a pleasant 'funk' to the style.
Some breweries produce exclusively barrel-aged beers, notably Belgian lambic producer Cantillon
, Belgian lambic blender Hanssens, and American brewery Jolly Pumpkin Artisan Ales
.
, to the water used for the brewing
of beer
, in order to bring out the flavour of the hops
. The name comes from the town of Burton upon Trent
which had several very successful breweries due to the chemical composition of the local water.
In the early 19th century, pale ale
was being successfully brewed in London. In 1822, the method had been copied by the Burton upon Trent brewer Samuel Allsopp
, who got a more hoppy tasting version of the beer because of the sulphate-rich local water. The clean, crisp, bitter flavour of beer brewed by Allsopp in Burton became very popular and by 1888 there were 31 breweries in the town
supplying demand for Burton Ale. The characteristic whiff of sulphur indicating the presence of sulphate ions became known as the "Burton snatch".
Later, the chemist C. W. Vincent analysed the waters of Burton and identified the calcium sulphate content as being responsible for accenting the hop bitterness in Burton Ale.
Burtonisation is used when a brewer wishes to accent the hops in a pale beer, such as a pale ale
. It is not used for dark beers such as stout
. A degree of sulphate ions in the water is also appropriate for emulation of the Czech
Pilsener
style, and sulphate ions are also distinctive of Dortmunder Export
.
Introducing magnesium sulphate into the brewing water, or "liquor", creates a rounder, fuller taste that enhances other flavours in the beer. However, it also has a laxative
effect.
(yeast
foam) to be expelled from the casks without leaving excessive amounts of head space within the casks; the system was quickly refined to separate any expelled beer from the wasted yeast, allowing it to flow back into the casks to continue fermentation.
The Burton Union is credited with maintaining the strains of yeast used in Burton brewing in a relatively stable state until the mid-20th century.
While not widely used in commercial beer production anymore, the Burton Union principle is often looked on as a technical challenge for advanced homebrewers, and a commercial approximation of the design is available for experimenters.
method used for the production of ale
s. During the early 20th century it was the most popular method of clearing trub
(inactive yeast and excess, staling and haze-forming protein
from the malted barley) during fermentation
for English ales. It is less commonly used today as it requires additional brewing vessels in a 2-tier system.
During the double dropping process the wort
(newly brewed, fermenting beer) is first fermented for a period of time before being transferred, under gravity or by other means, into a lower vessel where it continues fermentation. The dropping process has two primary effects on the beer being fermented: the trub that has settled during the first period of fermentation will be left behind, leaving a cleaner beer and a cleaner yeast
to crop from the beer for the next fermentation; the second effect is the aeration of the wort, which results in healthy clean yeast growth, and in certain circumstances butterscotch flavours from the production of diacetyl
.
Breweries using the double dropping process include Wychwood Brewery
who contract brew Brakspear
branded beers, and Flack Manor. Marston's
use the name Double Drop for one of their beers as they use the related brewing method of the Burton Union system. Wychwood transfers the wort the morning after the day fermentation started - typically about 16 hours later. This process originally took place at the Brakspear brewery in Henley. When Brakspear moved to the Refresh UK's brewery in Witney, a new brewery was built to include the original double dropping system. Brakspear claim that some of the flavour common to its beer is due to a combination of its very old complex multi-strain yeast and the dropping method which encourages it to produce the butterscotch-flavoured compound diacetyl
.
, the liquid extracted from malted barley, is fermented in the lower chamber, while the yeasty head
settles on the deck above. During the first stage of fermentation, the fermenting wort is periodically pumped from the bottom of the chamber over the yeasty head, to keep the yeast mixed in with the wort. Later, the mixing is stopped and the wort in the chamber allowed to settle and cool gently. Most of the yeast rises onto the deck, and is left behind when the beer is drained from the chamber. The whole process takes at least six days. However, beer straight from a Yorkshire Square vessel will still have a harsh flavour, so the residual yeast is allowed to ferment any remaining sugar, producing a little extra alcohol and carbon dioxide, which mellows the beer. This conditioning begins in tanks at the brewery and continues after the beer is filled into casks
, hence the phrase 'Cask Conditioned'.
Historically, the Yorkshire Square vessel was constructed from Yorkshire Sandstone
, but Welsh
slate
quickly proved to be the material of choice. A modern innovation is the so-called 'Round Square' pioneered by the Black Sheep brewery, which is built from stainless steel. The round shape makes it easier to clean out (a task that requires personnel to physically climb in to the vessels) between brewing cycles. The Yorkshire Square fermenting system dates back over 200 years ago, and is still used by Samuel Smith's and the Black Sheep brewery
. It may have developed with the assistance of Joseph Priestley
who, in 1722, delivered a paper to the Royal Society
on the absorption of gases in liquids.
Brewing
Brewing is the production of beer through steeping a starch source in water and then fermenting with yeast. Brewing has taken place since around the 6th millennium BCE, and archeological evidence suggests that this technique was used in ancient Egypt...
is the production of beer
Beer
Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...
through steeping a starch source (commonly cereal grains) in water and then fermenting
Fermentation (food)
Fermentation in food processing typically is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeasts, bacteria, or a combination thereof, under anaerobic conditions. Fermentation in simple terms is the chemical conversion of sugars into ethanol...
with yeast. Brewing has taken place since
History of beer
Beer is one of the world's oldest beverages, with the history of beer dating back to 6000 BC, and being recorded in the written history of Ancient Iraq. The earliest Sumerian writings contain references to beer...
around the 6th millennium BC, and archeological evidence suggests that this technique was used in ancient Egypt
History of Egypt
Egyptian history can be roughly divided into the following periods:*Prehistoric Egypt*Ancient Egypt**Early Dynastic Period of Egypt: 31st to 27th centuries BC**Old Kingdom of Egypt: 27th to 22nd centuries BC...
. Descriptions of various beer recipes can be found in Sumer
Sumer
Sumer was a civilization and historical region in southern Mesopotamia, modern Iraq during the Chalcolithic and Early Bronze Age....
ian writings, some of the oldest known writing of any sort. Brewing is done in a brewery
Brewery
A brewery is a dedicated building for the making of beer, though beer can be made at home, and has been for much of beer's history. A company which makes beer is called either a brewery or a brewing company....
by a brewer, and the brewing industry is part of most western economies.
There are several brewing methods, such as barrel aging, double dropping, and the Yorkshire Squares and Burton Union systems.
Barrel aging
BeerBeer
Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...
s are sometimes aged in barrel
Barrel
A barrel or cask is a hollow cylindrical container, traditionally made of vertical wooden staves and bound by wooden or metal hoops. Traditionally, the barrel was a standard size of measure referring to a set capacity or weight of a given commodity. A small barrel is called a keg.For example, a...
s to achieve a variety of effects in the final product. Sour beers such as Lambic
Lambic
Lambic is a very distinctive type of beer brewed only in the Pajottenland region of Belgium and in Brussels itself at the Cantillon Brewery and museum...
s are aged in wood (usually oak) barrels similar to those used to ferment wine, where a secondary fermentation takes place, usually including microflora other than Saccharomyces cerevisiae
Saccharomyces cerevisiae
Saccharomyces cerevisiae is a species of yeast. It is perhaps the most useful yeast, having been instrumental to baking and brewing since ancient times. It is believed that it was originally isolated from the skin of grapes...
. Other beers are aged in barrels which were previously used for maturing spirits. Porters
Porter (beer)
Porter is a dark-coloured style of beer. The history and development of stout and porter are intertwined. The name was first used in the 18th century from its popularity with the street and river porters of London. It is generally brewed with dark malts...
and stout
Stout
Stout is a dark beer made using roasted malt or barley, hops, water and yeast. Stouts were traditionally the generic term for the strongest or stoutest porters, typically 7% or 8%, produced by a brewery....
s are sometimes aged in bourbon
Bourbon whiskey
Bourbon is a type of American whiskey – a barrel-aged distilled spirit made primarily from corn. The name of the spirit derives from its historical association with an area known as Old Bourbon, around what is now Bourbon County, Kentucky . It has been produced since the 18th century...
barrels. Goose Island
Goose Island
-Places in Australia:* Goose Island * Goose Island ** Little Goose Island ** Inner Little Goose Island* Goose Island , two islands-Places in Canada:*Goose Islands...
's Bourbon County Stout was one of the first bourbon barrel-aged beers in the U.S., but the method has now spread to other companies, who have also experimented with aging other styles of beer in bourbon barrels (Allagash Brewing Company
Allagash Brewing Company
Allagash Brewing Company is an American brewery located in Portland, Maine.Founded in 1994 by Rob Tod, Allagash sold its first batch of beer in the summer of 1995. Tod had been working in breweries around the U.S. and recognized a void in the craft brewing movement...
, for example, makes a tripel
Tripel
Tripel is a term used by brewers mainly in the Low Countries, some other European countries, and the USA to describe a strong pale ale, loosely in the style of Westmalle Tripel. The origin of the term is unknown, though the main theory is that it indicates strength in some way...
aged in used Jim Beam
Jim Beam
Jim Beam is a brand of bourbon whiskey produced in Clermont, Kentucky. It is currently one of the best selling brands of bourbon in the world. Since 1795 , seven generations of the Beam family have been involved in whiskey production for the company that produces the brand, which was given the name...
barrels.)
By the early twenty-first century, the method of aging beer in used wine barrels had expanded beyond lambic beers to include saison
Saison
Saison is the name originally given to low-alcohol pale ales brewed seasonally in farmhouses in Wallonia, the French-speaking region of Belgium, for farm workers during harvest season...
, barleywine, and blonde ale. Commonly, the barrels used for this had previously aged red wine (particularly cabernet sauvignon
Cabernet Sauvignon
Cabernet Sauvignon is one of the world's most widely recognized red wine grape varieties. It is grown in nearly every major wine producing country among a diverse spectrum of climates from Canada's Okanagan Valley to Lebanon's Beqaa Valley...
, merlot
Merlot
Merlot is a darkly blue-coloured wine grape, that is used as both a blending grape and for varietal wines. The name Merlot is thought to derive from the Old French word for young blackbird, merlot, a diminutive of merle, the blackbird , probably from the color of the grape. Merlot-based wines...
, and pinot noir
Pinot Noir
Pinot noir is a black wine grape variety of the species Vitis vinifera. The name may also refer to wines created predominantly from Pinot noir grapes...
).
The Captain Lawrence Brewing Company
Captain Lawrence Brewing Company
-General:Captain Lawrence Brewing Company is an award-winning craft brewery located in Pleasantville, NY. The brewery is owned and run by head brewer Scott Vaccaro. Vaccaro, a homebrewer since 1995, trained in brewing science at UC Davis. He interned at Adnams Brewery, in the U.K...
is known for producing several beers aged in a variety of barrels. Notably their Smoke from the Oak Series are Porters
Porter (beer)
Porter is a dark-coloured style of beer. The history and development of stout and porter are intertwined. The name was first used in the 18th century from its popularity with the street and river porters of London. It is generally brewed with dark malts...
that have been aged in either merlot, bourbon, or rum
Rum
Rum is a distilled alcoholic beverage made from sugarcane by-products such as molasses, or directly from sugarcane juice, by a process of fermentation and distillation. The distillate, a clear liquid, is then usually aged in oak barrels...
barrels. Their Golden Delicious is a tripel
Tripel
Tripel is a term used by brewers mainly in the Low Countries, some other European countries, and the USA to describe a strong pale ale, loosely in the style of Westmalle Tripel. The origin of the term is unknown, though the main theory is that it indicates strength in some way...
that has been aged in barrels previously containing Apple Brandy
Brandy
Brandy is a spirit produced by distilling wine. Brandy generally contains 35%–60% alcohol by volume and is typically taken as an after-dinner drink...
or AppleJack
Applejack (beverage)
Applejack is a strong alcoholic beverage produced from apples, popular in the American colonial period.Applejack was historically made by concentrating hard cider, either by the traditional method of freeze distillation or by true evaporative distillation. The term applejack derives from jacking, a...
. Rosso e Marrone' is an Oud bruin
Oud bruin
Oud Bruin, also known as Flanders Brown, is a style of beer originating from the Flemish region of Belgium. The name literally translates as "old brown", referring to the long aging process which can take up to a year. It undergoes a secondary fermentation, which takes several weeks to a month,...
aged in wine barrels infected with Brettanomyces
Brettanomyces
Brettanomyces is a non-spore forming genus of yeast in the family Saccharomycetaceae, and is often colloquially referred to as "Brett". The genus name Dekkera is used interchangeably with Brettanomyces, as it describes the teleomorph or spore forming form of the yeast. The cellular morphology of...
, a species of wild yeast that lends a pleasant 'funk' to the style.
Some breweries produce exclusively barrel-aged beers, notably Belgian lambic producer Cantillon
Cantillon
Cantillon may refer to:* Joe Cantillon , baseball manager and umpire* Paddy Cantillon, hurler* Phil Cantillon, British rugby league footballer* Richard Cantillon , economic theorist* Cantillon Brewery, Belgian brewery...
, Belgian lambic blender Hanssens, and American brewery Jolly Pumpkin Artisan Ales
Jolly Pumpkin Artisan Ales
Jolly Pumpkin Artisan Ales is a microbrewery in Dexter, Michigan founded by Ron Jeffries in 2004. It operates two pubs in Ann Arbor and Traverse City, Michigan. Jolly Pumpkin produces a variety of unfiltered and unpasteurized "rustic country beers"....
.
Burtonisation
Burtonisation is the act of adding sulphate, often in the form of gypsumGypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
, to the water used for the brewing
Brewing
Brewing is the production of beer through steeping a starch source in water and then fermenting with yeast. Brewing has taken place since around the 6th millennium BCE, and archeological evidence suggests that this technique was used in ancient Egypt...
of beer
Beer
Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...
, in order to bring out the flavour of the hops
Hops
Hops are the female flower clusters , of a hop species, Humulus lupulus. They are used primarily as a flavoring and stability agent in beer, to which they impart a bitter, tangy flavor, though hops are also used for various purposes in other beverages and herbal medicine...
. The name comes from the town of Burton upon Trent
Burton upon Trent
Burton upon Trent, also known as Burton-on-Trent or simply Burton, is a town straddling the River Trent in the east of Staffordshire, England. Its associated adjective is "Burtonian"....
which had several very successful breweries due to the chemical composition of the local water.
In the early 19th century, pale ale
Pale ale
Pale ale is a beer which uses a warm fermentation and predominantly pale malt. It is one of the world's major beer styles.The higher proportion of pale malts results in a lighter colour. The term "pale ale" was being applied around 1703 for beers made from malts dried with coke, which resulted in a...
was being successfully brewed in London. In 1822, the method had been copied by the Burton upon Trent brewer Samuel Allsopp
Samuel Allsopp & Sons
Samuel Allsopp & Sons was one of the largest brewery companies operating in Burton upon Trent, England.Allsopp’s origins go back to the 1740s, when Benjamin Wilson, an innkeeper-brewer of Burton, brewed beer for his own premises and sold some to other innkeepers...
, who got a more hoppy tasting version of the beer because of the sulphate-rich local water. The clean, crisp, bitter flavour of beer brewed by Allsopp in Burton became very popular and by 1888 there were 31 breweries in the town
Brewers of Burton
Burton upon Trent had a unique position in the history of brewing, exporting beer throughout the world and accounting for a quarter of UK beer production at one time; emulation of Burton water is a prevalent brewing technique called Burtonisation. The town itself was dominated by the industry...
supplying demand for Burton Ale. The characteristic whiff of sulphur indicating the presence of sulphate ions became known as the "Burton snatch".
Later, the chemist C. W. Vincent analysed the waters of Burton and identified the calcium sulphate content as being responsible for accenting the hop bitterness in Burton Ale.
Burtonisation is used when a brewer wishes to accent the hops in a pale beer, such as a pale ale
Pale ale
Pale ale is a beer which uses a warm fermentation and predominantly pale malt. It is one of the world's major beer styles.The higher proportion of pale malts results in a lighter colour. The term "pale ale" was being applied around 1703 for beers made from malts dried with coke, which resulted in a...
. It is not used for dark beers such as stout
Stout
Stout is a dark beer made using roasted malt or barley, hops, water and yeast. Stouts were traditionally the generic term for the strongest or stoutest porters, typically 7% or 8%, produced by a brewery....
. A degree of sulphate ions in the water is also appropriate for emulation of the Czech
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
Pilsener
Pilsener
Pilsner is a type of pale lager. It takes its name from the city of Pilsen , Bohemia, in today's Czech Republic, where it has been developed since 1842, when a bottom-fermented beer was first produced. The original Pilsner Urquell beer is produced there today.-Origin:Until the mid-1840s, most ...
style, and sulphate ions are also distinctive of Dortmunder Export
Dortmunder Export
Dortmunder Export or Dortmunder is a pale lager that originated in the then industrial city of Dortmund in Germany. Originally brewed by Dortmunder Union in 1873, this soft pilsner style beer became very popular with industrial workers, and was responsible for Dortmunder Union becoming Germany's...
.
Introducing magnesium sulphate into the brewing water, or "liquor", creates a rounder, fuller taste that enhances other flavours in the beer. However, it also has a laxative
Laxative
Laxatives are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool, most often taken to treat constipation. Certain stimulant, lubricant, and saline laxatives are used to evacuate the colon for rectal and/or bowel examinations, and may be supplemented by enemas under...
effect.
Burton Union
The Burton breweries were known for a recirculating fermentation system known as the Burton Union. Invented in the 1830s, the Union system was a row of casks connected to a common trough by way of a series of pipes. The practical purpose of the Union system was to allow excess barmBarm
Barm cake is type of bun with flour on top. It has a characteristically strong flavour that comes from the traditional barm leaven made from a natural leaven with the addition of hops. However, the Barm Cake is more likely made from commercial yeast today....
(yeast
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
foam) to be expelled from the casks without leaving excessive amounts of head space within the casks; the system was quickly refined to separate any expelled beer from the wasted yeast, allowing it to flow back into the casks to continue fermentation.
The Burton Union is credited with maintaining the strains of yeast used in Burton brewing in a relatively stable state until the mid-20th century.
While not widely used in commercial beer production anymore, the Burton Union principle is often looked on as a technical challenge for advanced homebrewers, and a commercial approximation of the design is available for experimenters.
Double dropping
Double dropping, also known as the dropping system is a brewingBrewing
Brewing is the production of beer through steeping a starch source in water and then fermenting with yeast. Brewing has taken place since around the 6th millennium BCE, and archeological evidence suggests that this technique was used in ancient Egypt...
method used for the production of ale
Ale
Ale is a type of beer brewed from malted barley using a warm fermentation with a strain of brewers' yeast. The yeast will ferment the beer quickly, giving it a sweet, full bodied and fruity taste...
s. During the early 20th century it was the most popular method of clearing trub
Trub (brewing)
In the process of brewing beer, trub refers to the layer of sediment that appears at the bottom of the fermenter after yeast has completed the bulk of the fermentation...
(inactive yeast and excess, staling and haze-forming protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
from the malted barley) during fermentation
Fermentation (food)
Fermentation in food processing typically is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeasts, bacteria, or a combination thereof, under anaerobic conditions. Fermentation in simple terms is the chemical conversion of sugars into ethanol...
for English ales. It is less commonly used today as it requires additional brewing vessels in a 2-tier system.
During the double dropping process the wort
Wort (brewing)
Wort, , is the liquid extracted from the mashing process during the brewing of beer or whisky. Wort contains the sugars that will be fermented by the brewing yeast to produce alcohol.- Production :...
(newly brewed, fermenting beer) is first fermented for a period of time before being transferred, under gravity or by other means, into a lower vessel where it continues fermentation. The dropping process has two primary effects on the beer being fermented: the trub that has settled during the first period of fermentation will be left behind, leaving a cleaner beer and a cleaner yeast
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
to crop from the beer for the next fermentation; the second effect is the aeration of the wort, which results in healthy clean yeast growth, and in certain circumstances butterscotch flavours from the production of diacetyl
Diacetyl
Diacetyl is a natural byproduct of fermentation. It is a vicinal diketone with the molecular formula C4H6O2...
.
Breweries using the double dropping process include Wychwood Brewery
Wychwood Brewery
Wychwood Brewery is an English brewery founded by Paddy Glenny in 1983, and located in the town of Witney, Oxfordshire in the United Kingdom. It is owned by Refresh UK, a subsidiary of Marstons plc...
who contract brew Brakspear
Brakspear
WH Brakspear & Sons Ltd is the name of a brand of English beers and pubs, based in Henley on Thames, Oxfordshire. While the beer brewing and pub management sides of the business were originally unified, the brewing has since been sold to Wychwood Brewery owners Refresh UK.-History:The Brakspear...
branded beers, and Flack Manor. Marston's
Marston's
Marston's is the colloquial name for the brewer and pub operator Marston's plc . The company is listed on the London Stock Exchange and is a constituent of the FTSE 250 Index...
use the name Double Drop for one of their beers as they use the related brewing method of the Burton Union system. Wychwood transfers the wort the morning after the day fermentation started - typically about 16 hours later. This process originally took place at the Brakspear brewery in Henley. When Brakspear moved to the Refresh UK's brewery in Witney, a new brewery was built to include the original double dropping system. Brakspear claim that some of the flavour common to its beer is due to a combination of its very old complex multi-strain yeast and the dropping method which encourages it to produce the butterscotch-flavoured compound diacetyl
Diacetyl
Diacetyl is a natural byproduct of fermentation. It is a vicinal diketone with the molecular formula C4H6O2...
.
Yorkshire Square
A Yorkshire Square vessel is a two-storey system consisting of a shallow chamber approximately two metres high, above which is a walled deck. Cooled wortWort
Wort may refer to:* Wort, the liquid created by the mashing of malted barley to use in brewing beer* Worting, Hampshire, a large district and suburb of the town of Basingstoke, in Hampshire, England....
, the liquid extracted from malted barley, is fermented in the lower chamber, while the yeasty head
Beer head
Beer head is the frothy foam on top of liquid beer after it is poured in a glass. It is produced by bubbles of carbon dioxide rising to the surface....
settles on the deck above. During the first stage of fermentation, the fermenting wort is periodically pumped from the bottom of the chamber over the yeasty head, to keep the yeast mixed in with the wort. Later, the mixing is stopped and the wort in the chamber allowed to settle and cool gently. Most of the yeast rises onto the deck, and is left behind when the beer is drained from the chamber. The whole process takes at least six days. However, beer straight from a Yorkshire Square vessel will still have a harsh flavour, so the residual yeast is allowed to ferment any remaining sugar, producing a little extra alcohol and carbon dioxide, which mellows the beer. This conditioning begins in tanks at the brewery and continues after the beer is filled into casks
CASK
Peripheral plasma membrane protein CASK is a protein that in humans is encoded by the CASK gene. This gene is also known by several other names: CMG 2 , calcium/calmodulin-dependent serine protein kinase 3 and membrane-associated guanylate kinase 2.-Genomics:This gene is located on the short arm of...
, hence the phrase 'Cask Conditioned'.
Historically, the Yorkshire Square vessel was constructed from Yorkshire Sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
, but Welsh
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
slate
Slate
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering...
quickly proved to be the material of choice. A modern innovation is the so-called 'Round Square' pioneered by the Black Sheep brewery, which is built from stainless steel. The round shape makes it easier to clean out (a task that requires personnel to physically climb in to the vessels) between brewing cycles. The Yorkshire Square fermenting system dates back over 200 years ago, and is still used by Samuel Smith's and the Black Sheep brewery
Black Sheep Brewery
The Black Sheep Brewery is a brewery in Masham in the Borough of Harrogate in North Yorkshire, England.-History:The Black Sheep Brewery was established by Paul Theakston in 1991. Following a successful launch as a Business Expansion Scheme, it became a public limited company in 1992. Paul...
. It may have developed with the assistance of Joseph Priestley
Joseph Priestley
Joseph Priestley, FRS was an 18th-century English theologian, Dissenting clergyman, natural philosopher, chemist, educator, and political theorist who published over 150 works...
who, in 1722, delivered a paper to the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
on the absorption of gases in liquids.