The Open Guide to London: the free London guide - Differences between Version 8 and Version 7 of Real Ale
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What is Real Ale?
Ales include several types of beer with different flavours and qualities: Bitter, Mild, Porter, Stout.
An ale is the product of a fermentation process involving 4 ingredients:
What specifically real ale is, is determined by what happens to it after the fermentation process. If the yeast is kept alive in the bottle or cask into which the ale is decanted, a process of secondary fermentation, also known as conditioning, takes place, producing carbon dioxide in the bottle or cask. This means that no additional CO2 is required to serve the beer - it is naturally fizzy.
There are other ingredients commonly added into the brew:
- Gypsum is referred to in the trade as water treatment. This is used to compensate for differences in water mineral content in different parts of the UK.
- Sugars are commonly added to boost alcoholic content. Honey has become popular more recently, used in brews such as Waggledance and Honeydew. Unfortunately, sugars do not add to the flavour as nicely as the malt, but they are a cheaper ingredient. Sugars are sometimes added at the bottling/casking stage to assist secondary fermentation.
- Finings, usually Isinglass, which is a coagulant, made from parts of a sturgeon. These form a catalyst for precipitating out dead yeast cells - they do not end up in the resulting beer.
This is not a contradiction in terms. It is possible to brew a lager, and keep the yeast alive for secondary fermentation. The results are vastly superior to what is served up through a gas dispense. (IMO: Ivorw) (and Roger)
What's the difference between ale and lager?
These are definitively differences in the Yeast, but also different varieties of hop are used, and lighter coloured malt (crystal malt).
Ales use top fermenting yeast (which floats to the top of the liquid), whereas lagers use bottom fermenting yeast (which sinks). An important difference in the yeast types is the conditions required for fermentation. Ale yeast needs room temperature (20°C) and ferments in about a week. Lager requires a cold cellar (5-10°C), this is what the German word means; it ferments in about a month.
What to look for
Pubs that serve real ale have either hand pumps or barrels with taps (called gravity dispense). Beware of imitation hand pumps - you can usually tell from the beer if it has come out too fizzy and tasting of nothing.
When selecting bottled beers from the supermarket or off-licence, look out for the words bottle conditioned. If you see these words, they indicate that the beer has been bottled with live yeast, and the CO2 is naturally produced. This is the only real ale you get in a bottle - do not be misled by supermarket advertising.
Real Ale in the Cellar
Real Ale comes in casks - traditionally wooden, but usually made of metal these days. Casks come in different sizes:
- (Poly)Pin - 4 1/2 Gallons
- Firkin - 9 Gallons
- Bodkin - 18 Gallons
- Hogshead - 54 Gallons
Casks are barrel shaped, with two orifices - unlike kegs which are cylinrical with only one orifice. The one on the flat face contains a tap, and the one set in the curvature contains a spile (see below). Casks are racked with the flat faces nearly vertical - tilting downwards slightly.
In the cellar, when the beer has conditioned and is ready for serving, the tap is connected to a pipe, a beer line, and the hard non-porous spile (wood) is replaced by a porous soft spile (cork). The purpose of the soft spile is twofold:
- to vent off excess CO2 from the fermentation process
- to allow air to be drawn in to replace the vacuum as pints of beer are drawn off
At the end of each day, the soft spile is replaced by the hard spile, otherwise the beer will oxidise and perish too quickly. Similarly, the next day, the hard spile is replaced by the soft spile prior to serving.
Approved methods of cellar keeping
- Traditional: using the hard and soft spile method above. This can be delivered via hand pump (also known as a beer engine), poured directly from the cask (gravity dispense), or via electric pump.
- Race spile: This is a gadget which contains two valves to replace the function of a soft spile, and does not require replacing overnight.
Unapproved methods of cellar keeping
- Keg: Beer is delivered under pressure using CO2 gas.
- Nitro-Keg: known as smoothflow, cream and other such names. Beer is delivered under pressure using a mixture of Nitrogen and CO2 gases.
- Blanket CO2: Carbon Dioxide is injected into the top of the barrel, to preserve the beer and prevent contamination of the beer by air. Unfortunately, this kills the secondary fermentation process, hence the beer lacks flavour.
- Cask Breather the least of the evils. This mthod replaces the spile with a system of valves, which permits a mix of CO2 and compressed air into the barrel replacing pints drawn off.
Further information is available from Campaign for Real Ale
This entry also appears on the Everything2 Encyclopaedia, with links to other beer related writeups.
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