It is largely responsible for the beer’s bitterness and for certain aromas. Hops are climbing plants that can reach up to 15 meters in height, though more commonly measure between four and nine meters. They can withstand temperatures down to minus 30 degrees Celsius, but grow fastest in mid-summer: up to 50 centimeters per week.
Besides contributing to the bitter taste of beer, hops are important for forming a good foam and preventing the beverage from spoiling by inhibiting microorganism growth thanks to their antiseptic power. In short, without hops there is no beer… at least not as we know it.
HOW HOPS INFLUENCE BEER
The addition of hops usually has the main purpose of giving bitterness to the beer or adding distinct aromas and flavors. That is why there are bittering hops and aroma hops, as well as some that can be used for both purposes.
The type of hop and its purpose determine when it is added to the wort (the solution obtained by mixing crushed malt with water during mashing). Bittering hops are added at the beginning of the boiling process (kettle hopping). Hops for aroma and flavor are added at the end of the boil—during the last 30 minutes—or even during settling (late hopping). Three common late hopping techniques are flame-out, whirlpooling, and hopback.
Finally, there is dry hopping, a technique where hops are added cold during maturation, giving the beer the aroma of fresh hops.
ACIDS AND ESSENTIAL OILS: THE SECRET LIES IN THE GLANDS
Hop flowers have gender. It’s true: there are female flowers and male flowers. In beer production, female flowers are used because they are richer in acids and essential oils, which are the elements responsible for giving beer its characteristic aromas and bitterness. Both are concentrated in the lupulin glands, which is why most modern production does not use the whole flower, instead using extracts or pellets.
In aroma-focused hop varieties, acids make up 3% to 4% of the weight, a percentage that rises for bittering hops. In some cases, it can reach 20%. Essential oils represent 0.5% to 3% of the hop’s weight.
But why can’t all the hops be added at the same time? The answer lies in temperature. When added during boiling, alpha acids are converted into iso-alpha acids (isomerization), which are more soluble and therefore impart stronger bitterness to the beer. However, essential oils are lost during this process due to evaporation.
That is why, to preserve aroma, hops must be added at the end of the boil or even later, to prevent the oils from being lost. Depending on the hop variety used, these aromas can vary widely, from fruity to floral, spicy, woody, or earthy.
DID YOU KNOW
The isomerization rate is called hops utilization. It measures how many alpha acids are converted into iso-alpha acids in the finished beer. Normally, the value is between 25% and 35%, but it can reach 50%. When late hopping techniques are used, it can remain around 5%.
THE PATH TO CONQUEST
Almost until the end of the Middle Ages, beer was brewed using flavorings such as wild plants (for example, myrtle) or aromatic herb compounds, called gruit.
However, it is believed that the cultivation of hops had already begun in the 8th and 9th centuries in areas of Central Europe such as Bohemia (today part of the Czech Republic) and Bavaria, with particular prominence in the latter in the Hallertau region. Even today, these regions are major hop producers.
By the 11th century, hopped beer was already common in France, and in 1268 King Louis IX decreed that only malt and hops could be used in beer production. A similar path was followed by the Germans years later. First, in the 14th century, Emperor Charles IV established the Novus Modus Fermentandi Cervisiam, which introduced a new brewing method using hops. At that time, the climbing plant was known in Bavaria as “green gold.” Two centuries later, in 1516, Duke Wilhelm IV of Bavaria enacted the Beer Purity Law (Reinheitsgebot), which only allowed the use of malt, water, and hops.
Despite a more complicated introduction in England, where at one point authorities declared the plant an “aphrodisiac that could lead people to sin,” brewing beer with hops ultimately triumphed in Europe in the 16th and 17th centuries.
HOP VARIETIES
There are many hop varieties. Four of them are considered “noble hops”: Hallertauer Mittelfrueh, Spalter, Tettnanger, and Saaz. These hops are Czech and German and are primarily aroma hops.
Other notable examples include the English East Kent Golding (aroma and bitterness) and Admiral (bitterness), as well as the American Cascade (aroma) and Nugget (bitterness). The latter is the type of hop grown in Portugal, in two farms in Bragança of 6 hectares each. This national hop production is entirely purchased and exclusively used by Super Bock.
THE LARGEST PRODUCERS
The United States of America is the world leader in hop production. In Portugal, hops are grown commercially only on two farms in Bragança, totaling 17 tons per year.
United States of America
47.39
Germany
32.58
China
6.82
Czech Republic
6.79
Poland
3.25
Slovenia
2.16
Albania
2.07
North Korea
1.99
New Zealand
0.87
Portugal
0.017
