For the common people in the Middle Ages beer was a common beverage. It was safer than water that in the cities often was polluted, while beer was cooked and filtered during the preparation. And beer is nutritious: it contains grain and yeast, and is rich in vitamin B.
Students of the Wits University in South Africa in 2013 mimicked a 9,000 year old Chinese beer. Centuries ago, a person should have used daily two to three liters of beer, with an alcohol content of less than two percent.

moutenWe first malt barley, this means wetting on a warm, airy floor so that it germinates (12° to 15°C). They grow roots and a ’plume'. Enzymes are formed. Then the barley is dried again (40° to 65°C) and kilned at 80° -85° for lager, and at 115° for dark beer.
Malt grinding: crush into small pieces (not too fine, no flour!). The husks best remain whole, they serve later as a filter. This works easier if you have the malt slightly moistened. Quickly move to the next step.
Mashing: the seizure of approximately 4 liters of water on 1 kilo malt is kept at increasingly higher temperatures for a certain time to release every time other enzymes.
on 40° stir frequent without bringing air in the mixture
on 50°C for 15 to 30 minutes
62 à 63°C, with a rest period of 10 to 60 minutes.
(You can also work reverse, from high to low temperature.)

bierketel stokenFilter while it’s warm (e.g. via a converted cooler) on a perforated plate at 78°C: the pulp mass acts as a filter. You tap at bottom level the wort with a crane or siphon and pour it back on the top onto the filter cake until the drained wort is clear. Do not allow any, or as little air as possible in the mixture. Keep patiently filtering it again.
Then gently rinse the cake with warm water (80 degrees) before he is dry and gets air. Coil sufficiently. More coils gives lighter beer.
The wort is cooked well 1.5 to 2h. Add hops and let it boil for 15 to 60 minutes. Cooking the hop longer makes the beer more bitter.
Allow to settle and cool rapidly among many decantation and aeration.
Add brewer's yeast (wine yeast cannot convert maltose into glucose) starter and let ferment a day or 6. (Lambic Breweries let ferment the mixture spontaneously by wild yeast infection).
Bottling with some sugar to form carbon dioxide and let ripe.
Each phase (and certainly also the quality of the water (about pH 5.6)) affects the character of the beer.

In the early Middle Ages, beer also was flavored with herbs, it was called gruit.
Instead of hops also ivy was used.

Of the hop plant the unfertilized female flowers are used. The cone contains brewing technically spoken components as bitter substances (alpha acids), volatile oils and tannins. It is the bitter substances that give beer its characteristic flavor. These bitter substances also have a preservative effect. By cooking the alpha acids become isomerized, that means more bitter (twice) and more soluble (thirty times).

What is double and triple beer ?

Several explanations for these names came up. They are abbey beers. The ordinary 3 vol % beer for the refectory was made ​​ of one deposit (amount of material). With an (almost) doubling of the raw material was 6 % achieved: beer for guests and sales. Any heavier beers were therefore in imitation called triple (9 %). As even heavier beers are already put quad( ruppel, 9 % +) on the label.
Whether the vessels were distinguished in the Middle Ages with one sign for lager, and double crosses for beer for paying guests.
Lower beers are sometimes called single and have an alcohol content of 4.5 - 5.5.
Table beer has an original wort content between 1 and 4 degrees.

Not one man in a beer commercial has a beer belly.( Rita Rudner)