What are hops?

Hops are a cone-shaped flower. They are responsible for beer's bitterness, which balances the sweetness of the malt. They also contribute aromatic, floral, and perfumy flavors and odors. There are many different varieties of hops, each with its own bitterness and aroma qualities.

When should I add hops?

Bitterness is extracted from hops as they are boiled. Bittering hops should be added at the very beginning of the boil, which usually lasts for 60 - 90 minutes. Approximately 90% of hop bitterness is extracted after a 60 minute boil; over 95% of hop bitterness is extracted after a 90 minute boil. A 60 minute boil is most common.

Hop flavor is maximized by adding hops 10 minutes before the end of the boil. Nearly no hop flavor remains after 30 minutes of boiling.

Hop aroma comes from very volatile hop oils, and is maximized by adding hops at the very end of the boil. Almost no hop aroma remains after 15 minutes of boiling.

What is dry hopping? What is the best way to dry hop my beer?

An intense hop aroma, similar to the aroma of fresh, uncooked hops, can be achieved by dry hopping, or adding hops directly to the fermenter. Dry hops should be ideally added to beer as you rack from the primary fermenter into the secondary, just after the head has fallen back into the beer. Pellet hops can be poured right on top of the beer; they will float, absorb moisture, and form a green "muck" on top of the beer. Plug hops should be added to a sanitized muslin bag, and weighted down so they submerge. Dry hops should be in contact with the beer for two weeks to maximize the aroma. Worried about bacterial contamination? Hops are a natural preservative, and we have never known raw hops to cause infection

What are Home Bitterness Units (HBUs) or Alpha Acid Units (AAUs)? How are they calculated?

The easiest way to estimate the bitterness of a beer recipe is to measure it in Home Bittering Units (HBUs). This simple calculation allows you to accurately and consistently replicate recipes, despite fluctuating alpha acid contents. HBUs (a scheme used by Charlie Papazian) and AAUs (used by Dave Line) are the same thing. To calculate HBU for a 5-gallon batch, simply multiply the alpha acid content of the hops by the number of ounces used. For example, a recipe bittered with two ounces of our Perle hops at 7.0% alpha would have 7.0 x 2, or 14 HBUs of bitterness. If we made this recipe a month from now with 10.0% alpha Perle hops, we would need to use fewer ounces. 14 HBUs divided by 10.0% alpha would require 1.4 ounces. HBUs should only be calculated on hops boiled for 60 minutes or longer. Flavor and aroma hops do not contribute significantly to bitterness.