Herkules hops for high alpha bittering from Germany

A German hop built for alpha

Herkules was released by the Hüll hop research centre in Bavaria in 2005. It was bred for one thing above all: a lot of alpha acid per hectare. German crops typically measure between 12 and 17% alpha, which puts it among the strongest bittering hops grown there.

Unlike some high alpha varieties bred to be as neutral as possible, Herkules has a character of its own. Tasters describe it as spicy, peppery and resinous with a touch of pine. From a single early addition that character is faint. From larger or later additions it becomes part of the beer.

The maths of high alpha bittering

The case for Herkules is easiest to see with numbers. Take a 1,000 litre IPA that needs 50 IBU from the 60 minute addition, at 28% utilisation:

• With Herkules at 16% alpha: 50 x 1,000 / (0.16 x 0.28 x 1,000) = about 1,120 g.
• With a 4% aroma hop: 50 x 1,000 / (0.04 x 0.28 x 1,000) = about 4,460 g.

Four times the pellets means four times the vegetable matter in the kettle. That matter soaks up wort and leaves with the trub, so every extra kilo of hops costs you beer as well as money. On a big brewing year that difference in lost wort adds up. Our guide to hop extracts and cryo hops covers the next step down that path.

Cohumulone and the question of harshness

Herkules has a relatively high share of cohumulone among its alpha acids, commonly quoted in the thirties per cent. Older brewing wisdom held that high cohumulone hops give a coarser bitterness. The evidence on that is mixed. Plenty of brewers find Herkules bitterness clean enough at sensible doses. Our guide to the cohumulone debate sets out both sides.

What is clear is that very high doses in a light beer can taste rough. If you brew a pale lager at 20 IBU, a few hundred grams of Herkules is fine. If you push a pale beer past 60 IBU with Herkules alone, taste it carefully against a version bittered with a softer hop.

Where Herkules fits best

It earns its place in beers with enough malt and hop character to carry a little spice:

• IPAs and double IPAs, where it supplies the base bitterness under late American or Southern Hemisphere hops.
• Stronger lagers and bocks, where high gravity lowers utilisation and a high alpha hop keeps the hop load down.
• Dark beers, where roast and caramel hide any edge.

In a delicate helles at 18 IBU, a softer hop such as Perle or Hallertau Tradition is usually the better fit. Herkules would work, but you would be using a sledgehammer for a picture hook.

Swapping Herkules in or out

Its closest counterparts are other high alpha hops: Warrior and Magnum are cleaner, Bravo and Columbus are fruitier or more resinous and the Czech Agnus is similar in strength with a herbal profile. Whatever you swap, keep the IBU constant, not the weight.

High alpha hops also lose alpha acid as they age. Store them frozen at around minus 18 °C in sealed foil. A 16% hop that drifts to 13% over a hot, badly stored season will leave your IPA a fifth short on bitterness. The label will not tell you.

Scaling it down for a pilot or homebrew batch

High alpha hops are easy to overdose at small scale, because the weights get small and a few grams make a real difference. For a 20 litre pilot at 40 IBU with Herkules at 15% alpha and 28% utilisation, the working is 40 x 20 / (0.15 x 0.28 x 1,000), about 19 g. Weigh it on a scale that reads to a gram, not a kitchen scale that reads to five.

Add the pellets slowly to a rolling boil. A large dose of hop pellets dropped in at once can trigger a sudden foam over, especially before the hot break has formed. Stand back, add in two or three portions and keep the burner or steam valve ready to turn down. The same applies on a 1,000 litre kettle, where a boil over is a burn risk as well as a mess.

Before your next big beer

Take your current bittering hop, its certificate alpha and the weight you use. Recalculate the same IBU with Herkules from the certificate of the lot you can actually buy. Then work out the kettle loss you would save with roughly a quarter of the hop mass. That one calculation tells you whether a switch is worth testing on a pilot batch.

Common questions

What alpha acid does Herkules have?

Herkules typically measures 12 to 17% alpha acid, among the highest of German grown hops.

Does Herkules taste harsh?

At sensible bittering doses most brewers find it clean enough. At very high doses in light beers it can taste rough, so trial it against a softer hop first.

What can replace Herkules?

Other high alpha bittering hops such as Magnum, Warrior, Columbus or the Czech Agnus. Recalculate the weight for the same IBU from each lot's certificate.

Is Herkules only for bittering?

Mostly. Late additions bring a spicy, peppery and resinous character that suits some IPAs and dark beers but not delicate lagers.