methanethiol

Technical specification

Assessment

The best way to detect mercaptan odours in cider is as follows. Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary.

Amount of flavour per capsule

4.5 µg per capsule

Threshold

The flavour threshold of methanethiol in cider is 1.5 µg / l.

Origins

Methanethiol arises in cider production through yeast autolysis at the end of fermentation or during maturation. Formation of high levels of mercaptans by yeast can be indicative of a deficiency of amino acids in the apple juice.

Importance

Methanethiol is a component of the sulphury flavour character of cider. It is found in all ciders to a degree. Methanethiol is an off-flavour when present in cider in excess. Supplementation of juice with ammonium salts prior to fermentation can help control formation of mercaptans in ciders.

CAS registry number

The CAS registry number for methanethiol is 74-93-1.

Other names

• methyl mercaptan
• mercaptomethane
• methane thiol
• methyl sulfhydrate
• thiomethanol
• thiomethyl alcohol

Remarks

Methanethiol is the main thiol found in cider. Other thiols give similar flavour notes which have subtle differences in relation to their flavour associations.

Threshold distribution

Capsules per pot

10