A Guide To Using Aroma Hops In Brewing

Aroma hops are added to beer to add flavour and aroma, without contributing much to the bitterness of the beer. Aroma hops are typically added during the last 5-15 minutes of the boil, or at flameout, to maximise the amount of aroma. Aroma hops can also be added after fermentation in a process known as dry hopping. The type of hop used is important when it comes to the recipe and when it is used. Aroma hops are low in alpha acids, which means that not enough alpha acids are isomerised during the boil to add significant bitterness to the beer.

Add aroma hops during the last 5-15 minutes of the boil

When brewing beer, hops are typically added in three stages: bittering, flavouring, and aroma. However, some beers may have only one addition, while others may have up to five or six.

Aroma hops are typically added during the last 5-15 minutes of the boil or at flameout (when the kettle is removed from the heat). This is known as a late hop addition. Adding hops at flameout will produce the maximum amount of aroma.

Hop oils responsible for aroma are extremely volatile and will be driven off in the steam of the boil almost immediately, so aroma hops must not be boiled for long.

Late hop additions add aroma and aromatic oils to the beer. Aroma hops are low in alpha acids, with an alpha-acid percentage of less than 10%. This makes it difficult to add enough bittering to a beer with aroma hops alone.

However, since alpha acids isomerise at temperatures above 175°F (79°C), bittering can still occur with aroma hops. Due to the low amounts of alpha acids, it will not be significant.

The timing of hop additions is crucial in achieving the desired flavour profile. By adding hops at different times, brewers can create more complex and nuanced beers.

Add hops to the secondary fermenter or keg after fermentation

Adding hops after the fermentation process is known as dry hopping. This technique is used to add aroma and flavour without creating bitterness. The hops are added to the secondary fermenter or a keg and are left for up to several weeks, creating a strong hoppy aroma.

Dry hopping originated with British brewers who would add hops to a cask shortly before shipping. Nowadays, dry hopping refers to any addition of hops after the wort has been cooled. This can be done in the primary fermenter, secondary fermenter, or by adding hops directly to a keg.

The benefit of dry hopping is that the brewer can get as much flavour and aroma as possible into the final beer. This technique can give your beer a floral essence and an intense flavour that is desirable in hoppy beer styles like pale ales and IPAs.

There are a few drawbacks to dry hopping. Firstly, since the hops are not boiled, they are not sanitised. However, this is rarely a cause for concern as hops do not provide a supportive environment for most types of bacteria, and the alcohol content and low pH of the beer will suppress bacterial growth.

Another potential drawback is that some beer drinkers think dry hopping makes the beer taste "grassy" or "oily". This method gives a different kind of flavour and aroma compared to the traditional method of adding hops to the boil.

When dry hopping, it is recommended to use a hop variety that is considered a "flavour" or "aroma" hop, typically with a relatively low alpha acid rating of around 6% or less. Common hop varieties used for dry hopping include Cascade, Crystal, Willamette, East Kent Golding, Fuggle, Saaz, Hallertau, and Tettnanger.

The amount of hops used for dry hopping can vary depending on personal preference, but a normal" measurement is between 1-2 oz (28-56 g) of hops for a five-gallon (19-L) batch.

It is also worth noting that whole leaf hops take up more space in the fermenter and soak up more of the beer, decreasing the overall yield. Commercial breweries typically use pellet hops due to advantages such as shelf life, efficiency, and less beer absorption.

Use a hop back or jack to run hot wort through a bed of hops

Using a hop back or jack is a great way to add a burst of hop flavour and aroma to your beer. This technique is used by many micro and commercial brewers, and can also be used by home brewers.

A hop back is a device that is inserted in line as the beer is transferred and cooled from the hot boiler into the fermenter. The purpose of a hop back is to transfer delicate hop oils and aromas that would otherwise be boiled off in the boiler. The technique is used for many ales and related styles where a hoppy aroma is desirable.

The hop back is inserted at the hot end, closest to the boiler, to maximise the transfer of hop oils. Whole or plug hops are used, with the goal of maximising surface contact between the hot wort and the hops. Typically, 1-2 oz of hops are used for a 5-gallon home batch. Little actual alpha bitterness is added by a hop back, but a lot of fragile hop oils and aromas can be added. Therefore, it is best to use low-alpha-aroma hop varieties in your hop back.

Commercial brewers often make dual use of the hops from their hop back. After the hops have been used in a hop back, the fragile oils have been extracted but the high-alpha bittering hop oils remain. Therefore, brewers can take the hops used in the hop back and boil them to extract bitterness in a subsequent batch.

You can purchase small hop back devices from many home-brewing supply stores. These typically consist of a small watertight container that can be easily opened and sanitised before use. Hops are added to the container and it is sealed for use. An inlet and outlet tube flow the hot wort through the hop back, and then into either a counterflow chiller or other cooling device before the wort is transported to the fermenter.

You can also build a hop back at home from any watertight, heat-resistant container. One innovative design consists of nothing more than a ball canning jar with holes drilled into the top where tubes and fittings have been added to produce a watertight seal. If you create such a device, it is important to use lead-free solder when soldering the pieces together, and to check the system to make sure it is watertight before use.

Dry hopping: add hops to the fermenter or serving tank

Dry hopping is the process of adding hops (typically dried whole leaf or T-90 pellets) during or right after primary fermentation. It adds aroma and flavour without any bitterness to your beer. Hops contain compounds called alpha acids, which when heated during the boil, undergo a process called isomerization, providing the beer with bitterness. Boiling hops for a longer period of time leads to more isomerization and a more bitter finished beer.

Dry hopping preserves the delicate volatile oils that produce flavour and aroma. These oils do not survive a boil. The process gives your beer a mouth-watering aroma.

Whole Leaf vs Pellet

You can use both pellet and whole leaf hops for dry hopping. Pellet hops are a little more convenient and more readily available. Leaf hops take up more space in the fermenter and also soak up more of the beer, decreasing the overall yield. Commercial breweries use pellet hops because they have a longer shelf life, are more efficient, and result in less beer absorption.

Choosing Hops for Dry Hopping

Your beer's flavour profile and characteristics should dictate which types of hops you use. There aren't necessarily any wrong hops to choose from for dry hopping, but you should stick with aroma-forward hops.

Timing

Your beer should stay in contact with the hops for 2-4 days before it's bottled or kegged. After a few days, there's nothing more to gain from extending the time in contact with the hops. You've reached a saturation point where the aroma can start to fade.

Double Dry Hopping (DDH)

This is a brewing technique that has two different meanings. It could mean splitting the dry-hop additions at different times, for example, adding some hops during fermentation and some after fermentation. Or it could mean literally doubling the number of hops added during or after fermentation.

Loose vs Bagged Hops

Loose hops in the beer will give you much better results in terms of beer contact and overall aroma. If you must use a mesh bag, a large bag is better so your beer can flow more freely through the hops. A tight ball will decrease the overall surface area your hops can stay in contact with your beer.

Dry Hopping Under Pressure

Fermenting under pressure has become a popular topic in the homebrew world. Dry hopping under pressure will also help combat oxidation.

Keg Hopping

Keg hopping is adding hops directly to the serving keg to keep the beer's aroma fresher for longer. If you go this route, it is recommended to hop in a fine mesh bag so you don’t risk clogging your dip tubes with hops.

Use hops with a 1:1 ratio of alpha:beta acid contents

Hops are added to the brewing process to add aroma and bitterness. The strength of the hop character depends on the quantity of hops added and the point during the brewing process at which they are added.

Aroma hops have a 1:1 relationship between alpha and beta acids. While alpha acids are the source of bitterness in hops, beta acids are important when compared to the amount of alpha acids in the same hop. The ratio of alpha to beta acids dictates the degree to which bitterness fades during ageing.

When using aroma hops, it is important to note that the degree of isomerization and the amount of bitter flavour produced are dependent on the length of time the hops are boiled. Longer boil times will result in the isomerization of more alpha acids and, thus, increased bitterness.

There are several ways to add aroma hops to the brewing process. One way is to add the hops directly to the mashtun, which adds character to the beer without adding bitterness. Another way is to add the hops at the beginning of the lautering process, creating a smoother blended beer with little aftertaste. A third way is to add the hops during the bulk of the boil, which releases alpha acids and creates bitterness. Adding hops in the last 5-15 minutes of the boil is known as late hop addition, which adds aroma and aromatic oils to the beer. A further method is to add the hops after the fermentation process is complete, by adding the hops to the secondary fermenter or a keg and leaving them for several weeks, creating a strong hoppy aroma.

To maximise the aroma of hops, it is recommended to use a lot of well-preserved hops in the boil. Adding hops late in the boil, covering the kettle after late-hop additions, and using dry hopping with weighted mesh bags can also increase the aroma.

Frequently asked questions