Mouthfeel is more than just a “feeling”. It’s the way we experience the physical, thermal, and chemical characteristics of what we eat and drink. It includes everything: from the creaminess of a piece of chocolate to the dryness of a red wine to the tingling sensation from the carbonic acid in a beer.
What is mouthfeel?
The main part here is played by our sensory systems – in particular the trigeminal nerve, which is responsible for sensations such as heat (chili), coolness (mint), and dryness (tannin). And then there’s our saliva, too, which – like an invisible hero – distributes taste molecules and reinforces texture.
Taste vs. aroma – what is the difference?
We often use the terms “taste” and “aroma” as synonyms, but they’re not the same thing. Taste refers to the chemical compounds that are perceived by special receptors on the tongue and elsewhere in the mouth. These receptors react to molecules such as sugars (sweet), salts (salty), or acids (sour), and send signals to our brain which translates this information into taste experiences.
Aroma, on the other hand, is the perception of volatile compounds that are detected by the nose. These molecules, which are often referred to as “odorants”, activate the olfactory receptors and create the scents that we associate with foods – such as the fruity fragrance of strawberries or the smoky smell of barbecued meat.
Taste and aroma work hand in hand to create what we call “flavor” – the overall experience of taste, smell, and mouthfeel. And this is where it gets exciting: these senses interact. A hop-aromatic fragrance, for example, can intensify perceived bitterness. This interaction is so powerful that we sometimes confuse smells with tastes – a phenomenon known as “odor referral”.
And then there’s also mouthfeel – the physical sensations we experience when eating and drinking. It encompasses textures such as creaminess, crunchiness, or viscosity, as well as thermal and irritating sensations such as cooling (mint) or burning (chili). These perceptions are controlled by our somatosensory and chemosensory systems and contribute considerably to the overall flavor experience.
Not everyone perceives taste and aroma in the same way. Our gustatory sensitivity is strongly influenced by factors such as genetics, age, gender, and culture.
Mouthfeel in beer
Mouthfeel is a decisive factor in the overall perception of beer. It encompasses sensory characteristics such as:
- the tingling and the freshness caused by CO2
- astringency: i.e. the dry, contracting sensation that can be caused by polyphenols
- the soft, pleasant texture produced by polysaccharides and dextrins
- full-bodiedness: the sensation of “body” or “substance” resulting from the composition of the raw materials, the fermentation, and the technology used
These characteristics are not only decisive for the enjoyment of the beer, but also for its market acceptance. A beer that doesn’t have a well-balanced mouthfeel is often considered by consumers to be inferior. Alcohol-free and low-alcohol beers are a rapidly growing market. However, these beers face sensory challenges: without alcohol, an important flavor carrier is missing, as is the full-bodiedness and warming sensation offered by traditional beers. Consumers often describe alcohol-free beers as being “watery” or “lacking in balance”.
This is where hops have a lot to offer. The use of pellets added very late in the process or of dry hopping allows a wide variety of bitter compounds to enhance the mouthfeel. Similarly, low-molecular-weight polyphenols add to the astringency and sensory complexity. Intense hop aromas such as thiols, esters, and terpene alcohols – depending on their herbal, floral, or fruity character – can enhance both the mouthfeel and tastes such as sweetness, acidity, and bitterness.
The important thing is to find the right varieties, product form, dosage quantity, and dosage timing to best enhance the mouthfeel of alcohol-free beers. Alongside pellets, very specific hop oil fractions can also enhance the mouthfeel when added to the finished beer. This also applies to liquid hop extracts which can be used for dry hopping. In addition, brewers can take advantage of maltose-negative yeasts which create a special aroma profile while the unfermented sugar adds to the mouthfeel. This is also helped by the scope provided by working with very low alcohol levels, because even very low ethanol content can help the hops to enhance the mouthfeel.
Sensory assessment of mouthfeel in beer still plays too small a part in the tasting schemes traditionally used in the brewing industry. When all the various parameters that affect mouthfeel are taken into consideration, it is important for a tasting scheme to identify those that are relevant and to consider how they can be evaluated. This would include terms such as dry, cooling, warming, tingling, coating, smooth, viscous, full-bodied, creamy, mineral, alkaline, or chalky. These can be used simply as descriptors (CATA, check all that apply) or be rated additionally according to intensity levels.
There are also electronic instruments available for quantifying mouthfeel in numerical values. These include soft tribology (the measurement of friction in foods), electronic tongues, or quartz crystal microbalances (QCM), which use an oscillating quartz crystal as a sensor. However, the best testing device is and remains the human being.
