Tired of getting disapproving looks from beer geeks? Don’t know your esters from phenols? Don’t fear… in this column, we will demystify four key areas of beer to help you impress at the pub.
4. Esters
Ahhhh… the memories of fourth-form Science class. The roar of the Bunsen burner. The smell of fake banana and pineapple esters. Yes, all beers have naturally occurring levels of esters. An ester is a fruity-sweet volatile compound made from an organic acid and an alcohol, formed by enzymes in the yeast during fermentation. Esters are important flavour contributors to beer. Ester ‘notes’ may be as exotic as banana, pear, orange, and bubblegum. The detection of esters is dictated by a couple of things—the amount of ester generated by the yeast during fermentation and the flavour threshold of the drinker. Over 50 different esters have been detected in beer but the main contributors to flavour are isoamyl-acetate (banana), ethyl-acetate (solvent, plastic) and ethyl-hexanoate (red apple tending to a hint of aniseed).
3. Bitterness Units
One of the five basic senses of the tongue is bitterness. If your tongue was a 4-4-2 football formation (with the strikers being the taste-buds on tip of your tongue) then bitterness would be the sensation from the fullbacks and centre-backs. Beer chemists like to determine bitterness levels in the laboratory by using solvents to extract isomerised acids from the beer and then measuring their levels using a spectrophotometer. When the malty beer mix is boiling, hops are added. The hops have acid compounds that get isomerised into more bitter compounds during the boil. The thing is that measuring bitterness units is only half the story. The perception of bitterness is also related to the malt that is evident in a beer. A glass of Steinlager may be perceived as more bitter than a glass of mike’s Premium Organic Ale even though they are both about the same number of bitterness units.
2. Phenols
Question: Are phenols a good or bad thing in beer? Answer: It depends. Phenols are characterised by clove, pepper, Band Aid and medicine cabinet flavours, produced by yeast during fermentation. Sometimes the brewer’s yeast strain is expected to produce balanced proportions of these flavours. For instance, the clove note of a German Hefeweizen or peppery character to a Belgian Ale. The not-so-good variety of phenols can come from ‘wild yeast’—the naturally occurring yeast from the surrounding environments that can infect the beer and lead to sharp medicinal qualities. Wild yeast can produce a sharp band-aid flavour that is reminiscent of drinking a mix of Dettol and mouthwash. When you taste phenols in a beer, ask yourself: has the brewer tried to achieve this flavour using a Belgian or Hefeweizen ale strand or is it likely due to a contamination?
1. Terroir
Terroir can be described as the special characteristics that the geography and climate of an area contribute to the crops it produces. In beer, this can be easily seen in the hops from around the world. Hops only grow successfully in very limited geographies in the world. When hops are compared from different regions, common flavour notes are determinable from those geographies. English hops have a spicy, earthy quality. German hops have been described as refined with elements of sandalwood and furniture polish. American hops tend to emphasize a pine and citrus. New Zealand hops have strong elements of grassiness, tropical fruit and an interesting gooseberry-lime quality. Some agricultural experts put New Zealand’s terroir down to the increased levels of ultra violet light. It’s interesting to make comparisons between New Zealand’s hops and grapes: the classic description of NZ Sauvignon Blanc being “cat’s pee on a gooseberry bush” could be similarly applied to a number of New Zealand’s hops.