Behind the scenes:

Beer is the world's oldest and most popular alcoholic beverage. It is produced by the fermentation of sugars derived from starch-based material—the most common being maltedbarley.  

The starch source is steeped in water. Enzymes in the malt break down the starch molecules, producing a sugary liquid known as wort, which is then flavored with hops, which acts as a natural preservative. Yeast is then used to cause fermentation, which produces alcohol and other waste products from anaerobic respiration of the yeast as it consumes the sugars. The process of beer production is called brewing.

Ale (e.g. London Pride) is commonly defined by the strain of yeast used and the fermenting temperature. Ales are normally brewed with top-fermenting yeasts, most commonly Saccharomyces cerevisiae. The important distinction for ales is that they are fermented at higher temperatures and thus ferment more quickly than lagers.

Ale is typically fermented at temperatures between 15 and 24 °C. At these temperatures, yeast produces significant amounts of esters and other secondary flavour and aroma products, and the result is often a beer with slightly "fruity" compounds resembling apple, pear among others. Typical ales have a sweeter, fuller body than lagers.

Lager (e.g. Carlsberg) is the English name for bottom-fermenting beers of Central European origin. They are the most commonly consumed beers in the world. The name comes from the German lagern ("to store"). Lagers originated from European brewers storing beer in cool cellars and caves and noticing that the beers continued to ferment, and also were clear of sediment. Lager yeast is a bottom-fermenting yeast (e.g., Saccharomyces pastorianus), and typically undergoes primary fermentation at 7–12 °C (the "fermentation phase"), and then is given a long secondary fermentation at 0–4 °C (the "lagering phase"). During the secondary stage, the lager clears and mellows. The cooler conditions also inhibit the natural production of esters and other byproducts, resulting in a "cleaner" tasting beer.

Stout (e.g. Guinness) and porter are dark beers made using roasted malts or roast barley. The name Porter was first used in 1721 to describe a dark beer popular with street and river porters of London that had been made with roasted malts. This same beer later also became known as stout, though the word stout had been used as early as 1677. The history and development of stout and porter are intertwined.

Cider (e.g. Magners) is not a beer but an alcoholic beverage made mainly from the fermented juice of apples, though pears are also used; in the UK, pear cider is known as perry. While any variety of apple can be used certain cultivars are preferred in some regions, and may be known as cider apples. The drink varies in alcohol content from less than 3% in French cidre doux to 8.5% or above in traditional English ciders. Cider is very popular in the United Kingdom, especially in South West England. The UK has the highest per capita consumption as well as the largest cider producing companies in the world.