The science behind how you taste your beer
Do you have a beer preference? Hate hoppy beers? Dislike dark beers? Say no to sours? Or perhaps you love them all and can pick out subtle notes of apricot or pine.
Remember that map of our tongues which locates different areas to be responsible for different tastes? Sweet and salty at the front, bitter at the back, and sour at the sides? This isn’t quite how taste works. Our tongues are covered in thousands of tastebuds which react to molecules and ions that pass over them when we eat or drink. Each tastebud has 50 to 100 receptors capable of sensing tasting bitter, sweet, salty, sour and umami over the whole tongue, which send signals to the brain to create a flavour.
Flavour perception is influenced by more than just the tongue. Hold your nose when you take your first sip of beer. Then release. You will notice the burst of flavour only hits you once you can breathe through your nose again. Most of our sense of taste is dominated by our perception of smells. Smell and taste are directly linked due to having the same receptors in the brain. We often describe tastes as if they are scents – for example, a beer may have a taste of what fresh wood shavings smell like. We assume you have never actually tasted wood shavings, yet you can imagine their taste based on their scent.
If you have ever had a flat, or warm beer you will know that mouthfeel plays a big role in how a beer tastes. Mouthfeel is the textural component of the beer. It involves the perception of viscosity, pH, temperature, carbonation and alcohol content, and plays an important role in how you experience a beer. The carbonation of your ale will change how flavours are delivered to your tongue and carried through to the nose through your throat. Even the size of the bubbles in your beer will influence your taste (more about this in a future blog).
Interestingly, sight will influence how you taste your beer too. If your beer is dark brown you will likely have preconceived ideas about how that beer should taste. A rose-coloured sour may give a perception of berries or sweet flavours that you are then more attuned into perceiving on first sip. My most stark experience of this was my first White Stout (‘So Long Darkness..?’ By Stone & Wood). In the glass it is a bright, pale golden liquid, much like a hazy IPA in appearance but with strong flavours of rich cocoa and coffee – flavours you associate with seeing deep brown colour – the ultimate optical illusion.
Now if you’re reading this thinking, huh? Beer is beer – it’s either dark, light or hoppy. Well, let me introduce you to the flavour wheel.
Dr. Morten Christian Meilgaard (1928-2009), was a Denmark born research chemist who specialized in yeasts. He was fascinated by the different flavour profiles that can be created through fermentation, and how they can be perceived. In the late 1970’s Meilgaard and his colleagues decided to come up with a list of flavour terms to address the “chaos” existing in beer flavour terminology. They created the beer flavour wheel. Variations of this beer flavour wheel are used by brewers and beer consumers around the world to describe complex flavours in beer. My favourite description from the flavour wheel is Isodoform which is the smell or taste from band-aids or duct-tape. While not necessarily a favourable flavour in beer, it is a flavour we all immediately know when someone describes it. Also fascinating are the chemicals produced by the yeasts through fermentation which give us these flavours - Ethyl Acetate for example, is the chemical that tastes and smells deeply fruity, like yellow stone fruit, with a brandy note.
Why can taste differ so much from person to person? Well that could be caused by many things. Genetics is thought to play a role in which signals can be perceived by a person. About a quarter of the population have a variant of the TAS2R38 gene which makes them hypersensitive to bitter tastes found in some leafy greens, coffee and even IPAs. Supertasters make up around one quarter of the population, with women more likely to be supertasters than men. These people have more tastebuds on their tongues and can pick certain flavours out in much smaller quantities than the rest of us. Since smell is so tightly linked to taste, if you have had a cold your flavour perception will be thrown off due to lack of smell sensitivity. This is especially common in smokers. What you have eaten lately can also contribute to taste perception. Some flavouring agents such as artificial sweeteners can bind tightly to your taste receptors for minutes or even up to an hour. The flavours in your beer will not be able to be perceived in this time and can cause your beer to taste very different. Flavour can be something as simple as contrast too – hoppy beers may taste more bitter if you have been eating something sweet beforehand. It is good practice to analyse the taste of your beer over several mouthfuls. Professional beer judges, or cicerones will rinse their mouths between beers and cleanse their palates with a salt free cracker.
If you are interested in how professional beer judges taste beer, take a look at this article https://vinepair.com/articles/how-to-taste-beer/ based off of the official beer judge certification program guidelines.
The next time you take a swig of your caramel coated stone-fruit with notes of fresh sawdust and a bitter, leathery finish, think of the chemistry swirling around your mouth, over your tastebuds sending signals to your brain to create the profound thought of “not bad”.