The Magic Behind Beer Aroma: Ingredients To Process

The aroma of a beer is one of its most important yet overlooked characteristics. Aroma is a major sense that ties directly into the primitive parts of the brain, and it's what allows us to differentiate between different tastes. The sense of smell is so powerful that it can transport the human mind to the past, over years or even decades. The interplay of taste and smell significantly affects how our brains perceive flavour. Beer aroma originates from the malt, hops, yeast, and any additional ingredients added during the brewing process. The type and amount of hops used, for example, can lend a floral, citrus, or spice aroma to the beer. The yeast used also plays a role in the beer's aroma as it produces esters during the fermentation process, which give off a fruity flavour and scent.

The role of malt, hops, yeast and other ingredients

The role of malt, hops, yeast, and other ingredients in creating beer aroma

Malt forms the very soul of beer. It is the cereal seed that has been tricked into thinking it is about to grow into a plant, only to be denied the opportunity. Malting makes the nutrients and enzymes available to brewers, which otherwise would have been used by the seed to grow into a plant. While almost any cereal grain can be malted, barley is the most popular choice for brewing. Barley's morphology and biochemical constitution make it the ideal brewer's grain. The outer husks that surround barley kernels protect the grains during malting and collectively form an effective filter during lautering (wort runoff).

Barley is rich in diastatic enzymes, which convert starches to sugars during mashing. In fact, barley is so rich in these enzymes that it can even convert the starches of other grains as it converts its own. The sugars in the malted barley interact with the yeast to create aromas and flavours that range from fruits to spices.

The hops in beer provide the bitter flavour that balances the sweetness of the malt. The bitter flavours in hops come from the alpha acids in the hop flower. The higher the alpha acid level, the more bitter the beer will be. The classic hop smell comes primarily from the essential oils in hops and is more prevalent when added at the end of the brewing process. The most common essential oils are alpha-caryophyllene and humulatriene, which create pine, citrus, tobacco, and sage aromas in beer.

Yeast and sugars interact in the malt, creating aromas and flavours that range from fruits to spices. Different types of yeast create different tastes and aromas, as does the brewing temperature. The main flavour contributors from yeast are esters and phenols. In general, the warmer the fermentation, the more esters are present. Ale yeast prefers warmer temperatures compared to lager yeast, and warm fermented ale yeast can create a lot of isoamyl acetate, which makes a sweet candy banana aroma.

Other ingredients that can be used in the brewing process include wheat and rye. Wheat has long enjoyed celebrity status in Bavarian Weißbier, Berliner Weisse, Belgian wit, and American wheat ale. Wheat malt, because of its soft, grainy flavour, is largely responsible for the refreshing nature of German Hefeweizen, Belgian Wit, Berliner Weisse, and American wheat beers. Its high protein content lends haze to the final beer.

Rye has recently gained prominence in American craft ales and lagers. It brings a spicy flavour and silky, almost oily, texture to traditional German Roggenbier and exciting new American craft beers.

How glassware affects aroma

The glass you use to drink beer has a significant impact on its aroma. Firstly, drinking beer from a glass is better than drinking it from a can or bottle as it allows you to enjoy the full flavour. Glass provides a large surface area for carbonation bubbles, stimulating the olfactory and taste receptors on the tongue more than other containers. The open structure of a glass also allows all the beer's aromas to escape.

The shape of the glass also makes a difference. Different styles of beer usually go best with a certain type of glass. For example, porter beer usually tastes better in a non-Nike pint glass because it tapers at the top, which helps keep the beer's foam in place. Dark beers lend themselves well to this type of glass, as it provides a lacy structure through which the colour and aroma can be appreciated. Wheat beer, on the other hand, is often served in a wheat beer glass, which accentuates its cloudy appearance while releasing its rich aroma.

The shape of the glass also affects how the beer hits your palate when you take a sip. The long, straight trajectory of a pilsner glass will direct the beer toward the back-mid mouth, invigorating you with the cold, refreshing mousse. By contrast, the flared lip of a tulip glass for a high-gravity porter will introduce the dense, powerful beer gently into your mouth, arriving gracefully between the lip and gums.

The glass's shape also aims to highlight the roasted malts, rich coffee, and chocolate notes in stouts. The relaxed, open shape of a glass designed for stouts and porters allows the drinker's nose to comfortably get close to the beer to sniff out more nuances.

The temperature of the beer also makes a difference to its aroma. Colder beer means less fizz, and less fizz means less aroma. Beer is best enjoyed at its optimum temperature, and each beer style has its own temperature range. The glass plays a role in this: for example, a stemmed glass or a slim glass can help keep the beer colder for longer.

The science of smell

When it comes to beer, it's not just about the taste—aroma plays a crucial role in the overall drinking experience. The sense of smell is powerful, with strong links to primitive parts of the brain that evoke emotions and memories. It's no surprise then that aroma significantly affects how we perceive flavour.

The Role of Aroma

The interplay of taste and smell is key to how our brains interpret flavour. While our taste buds play a role, they can't deliver the full story. A blocked nose while eating makes for a rather depressing dining experience. Without smell, we lose much of the flavour. This is why taking the time to breathe in the aroma of a beer is so important.

The Art of Smelling Beer

Assessing beer aroma starts with pouring it into a glass. Keeping it in the can or bottle stifles the volatile compounds. A good tasting glass should be shaped inward to capture the aromas while being wide enough to accommodate your nose. When you first open the container, the beer aroma is volatile, and you'll get a sense of the most prominent notes.

There are several techniques to enhance your appreciation of beer aroma:

• The Drive-By: Pass the glass under your nose and breathe in to capture the top notes.
• Short Sniffs: Put your nose in the glass and take short, sharp sniffs to get the next layer of aroma.
• Seal and Swirl: Cover the glass, swirl the beer, then uncover and take a deep sniff to capture the deepest notes.

Sources of Beer Aroma

The aroma of beer originates from the malt, hops, yeast, and any additional ingredients used in the brewing process.

• Malt: Malted barley, the base ingredient of beer, contributes a wide range of aromas depending on how toasted the grains are. Darker malts evoke aromas like coffee, chocolate, and roasted notes. Lighter malts add doughy and grainy aromas.
• Hops: Hops are responsible for the characteristic hoppy aroma of beer. Centuries of breeding have produced varieties that offer an array of scents, including floral, citrus, and spice. The amount of hops used also affects the intensity of the aroma.
• Yeast: Yeast plays a crucial role in beer aroma, producing esters during fermentation that give off fruity flavours and scents. Different yeast strains result in varying esters, from banana to clove.
• Other Ingredients: Additional ingredients can further enhance the aroma, such as the orange, raspberry, and lavender notes in the Lily Ale by Bur Oak Brewing Company.

The Chemistry of Beer Aroma

The complex aromas of beer arise from specific organic chemicals. For example, diacetyl gives a buttery or butterscotch aroma, while iso-amyl acetate smells like bananas. The bitter flavours in beer come from alpha and beta acids found in hops, with the main alpha acids being humulone, cohumulone, and adhumulone. Essential oils in hops, such as myrcene, humulene, and caryophyllene, also contribute to the aroma and flavour profile.

Individual Variations in Aroma Perception

It's important to note that individuals respond differently to aromas due to genetic makeup and experiences. Our inherent abilities to detect and interpret aromas vary, leading to different beer preferences. For example, some people are genetically unable to smell linalool, a major hop aromatic component with a floral aroma.

The brewing process

The wort is then strained and transferred to a brew kettle, where hops and other ingredients are added. The boiling process sterilises the wort, and the hops add bitterness and flavour to the beer. Any solids are then separated, and the mixture is cooled to a temperature where yeast can be added safely.

Yeast is added in a fermentation tank, where the beer is left to ferment, and sugars are converted into alcohol. The yeast also produces esters and phenols, which give off a fruity flavour and scent. The beer is then moved to a maturing tank, where it remains for varying lengths of time depending on the style of beer. Finally, it is filtered and bottled.

The type of yeast and the brewing temperature will affect the aroma of the beer. Ale yeast, for example, prefers warmer temperatures and can create a sweet candy banana aroma. The darker the malt, the more likely it is to have a dark fruit and jam flavour, as well as a cotton candy smell.

Hops are also key to the aroma of the beer, with essential oils from the hops responsible for the bulk of the aroma and flavour. The most common essential oils are alpha-caryophyllene and humulatriene, which create pine, citrus, tobacco, and sage aromas. Hops with higher levels of myrcene will add a citrus or piney aroma, while hops with more caryophyllene will contribute a spicy flavour.

The addition of other ingredients during the brewing process can also affect the aroma of the beer. For example, if the malt is dried with a smoky agent like peat, the beer can take on a smoky flavour.

Aroma techniques

The aroma of a beer is one of its most important yet overlooked characteristics. It is key to understanding and appreciating the flavour of the beer. Aroma detection involves specific sensory receptors in the nose being stimulated by volatile chemicals in the air we breathe.

The Drive-By

Pass your beer glass back and forth under your nose, breathing in as you do so. This will give you the top notes of the beer's aroma.

Short Sniffs

Put your nose in the glass and take lots of short, sharp sniffs to get the next layer of aroma.

Swirl and Sniff

Seal the glass with your hand, swirl the beer, then put the glass under your nose, remove your hand, and take a deep sniff. This will allow you to detect the very deepest notes of the beer's aroma.

Coat the Glass

Coat the surface of the glass with beer by swirling it before smelling. This allows a thin film of beer to evaporate into the air, making the aromatic molecules available to your olfactory receptors.

Breathe Deeply

Breathe in sharply a few times, rather than taking one long sniff, to better assess the beer's aroma.

Retro-Nasal Smelling

Note the aroma generated as you swallow. This arises retro-nasally from the back of the nose and can provide a more sensitive detection of less concentrated aromas.

Frequently asked questions