Methional Flavour Standard

What Is Methional/Mercaptan Flavour in Beer?

Methional flavour is an off-flavour characterised by distinctive mashed potato and sulphurous aromas that develop in beer during storage and processing. The chemical compound responsible is 3-methylsulfanylpropanal, which becomes detectable at concentrations as low as 3 mg/L.

What Causes Methional/Mercaptan Flavour in Beer?

Methional/Mercaptan flavour develops through two primary pathways :

1. Beer Ageing Process
– Primary cause : Natural oxidation during storage and ageing
– Timeline : Develops progressively over time, particularly in stored beer
– Impact : Creates characteristic off-flavours that compromise beer quality

2. Maillard Reaction During Malting
– Process : Occurs when flavour compounds from the Maillard reaction interact with methionine
– Mechanism : Strecker degradation converts methionine into methional
– Source : Originates from malt processing and can carry through to finished beer

How to Recognise Methional Flavour : Sensory Terms

Methional presents distinct sensory characteristics that trained tasters can identify :

Flavour Characteristics :
– Mashed potato – The most recognisable aroma profile
– Peeled potato – Fresh, starchy vegetable notes
– Sulphurous – Distinctive sulfur-like undertones

What are the Professional Applications of the Methional Flavour Standard?

The Methional Flavour Standard is essential for various beer industry professionals and organisations focused on quality control and sensory evaluation :

– Brewing industry professionals use it for quality control and detecting ageing-related off-flavours in beer production and storage.
– Quality control managers rely on it to maintain product consistency and investigate customer complaints related to methional defects.
– Laboratory professionals utilise it for independent beer analysis, shelf-life testing, and brewing process optimisation.
– Educational institutions and certification bodies incorporate it into training programs for beer judges, brewers, and sensory analysts.

By using the Methional Flavour Standard, professionals can accurately recognise, measure, and evaluate methional character (mashed potato, sulphurous off-flavours) in beer, ensuring product quality and consistency.

Other Information

– Flavour level : 3- 8 mg / l
– Typical detection threshold : 3 mg/L
– Sensory impact level : Noticeable off-flavour above 5 mg/L

This is one of several flavours that can occur as part of the beer oxidation process. Others are dependent upon the type of beer and its stage of oxidation. Please contact us for more information about other oxidation and ageing flavours.