Brettanomyces, often referred to as “Brett”, is a family of yeasts. Brettanomyces is often considered a contaminant, giving a beer some “funky”, sour flavors. They are however essential to brewing sour styles such as Lambic and Gueuze and sometimes present in other styles such as saisons, farmhouse, Oud Bruid and Flanders red ales. There are […]


Saccharomyces, “sacc”, “sacch”, is a family of yeasts that ferments maltose sugars to create alcohols and CO2. Saccharomyces cerevisiae, “the sugar fungus of the beer”, is the family of yeasts that we commonly refer to as “top-fermenting” ale yeasts. Saccharomyces pastorianus, named in honour of Louis Pasteur, is the yeast that we commonly refer to […]


Relax, Don’t Worry, Have A Homebrew We all mess up, either through misunderstanding something, through clumsyness or through the lack of equipment or facilities. Personally I always screw something up while brewing, be it forgetting to shut a tap, forgetting to add something or simply making a mess. I usually ferment to hot (living in […]


Esters is a large (largest?) group of flavor compounds, in beer usually contributing fruity aromas and flavors. Esters can come in the form of hop essential oil sulfurs, or be formed during the fermentation. While most beer yeast has been selected for producing as few off-flavors as possible, Belgian and Bavarian (banana, clove) yeast is […]

Fatty Acids

Fatty acids are minor constituents of wort and increase in concentration during fermentation and maturation. They give rise to “goaty”, “soapy”, or fatty flavors and can cause a decrease in beer foam stability.

Organic Acids

The most important organic acids found in beer are acetic,citric, lactic, malic, pyruvic and succinic acids. They confer a “sour” or“salty” taste to beers. Some of these organic acids are derived frommalt and are present at low levels in wort, with their concentrationsincreasing during fermentation.

Sulfurs (Thiols)

0 – 1% of a hop’s essential oil. Very low perception threshold. Difficult to measure. Recently been linked to aromas such as passion fruit, tropical fruit, sauvignon blanc grapes and other exotic aromas that characterize hops such as Citra and Mosaic.

Hop Essential Oils

A hop’s essential oils contributes most of the typical hop aromas. The oils consists of three main groups of compounds: hydrocarbons, oxigenated hydrocarbons and sulfurs (thiols).

Harper’s Scale

There are hundreds of aromas commonly found in hops, however Harper’s scale, published in 1985 in the Atlas of Odor Character Profiles, is today often seen as the standard. The scale proposes twelve main aromas: Floral: Elderflower, chamomile blossom, lily of the valley, jasmine, apple blossom, rose, geranium, carnation, lilac, lavender Citrus: Grapefruit, orange, lemon, […]

Oxygenated Hydrocarbons

20 – 50% of hops essential oils. More soluble and aromatic. Their aromas, or new ones resulting from the fermentation process, are more likely to shop up in finished beer. Common Oxygenated Hydrocarbons There are hundreds of oxygenated hydrocarbons in hop oils, but the below ones constitutes a majority of the composition. Citronellol Geraniol Linalool […]