[ Methanol, a very toxic alcohol, is always present, in small amount in a wine. Contrary to what is generally thought, it is not formed during the fermentation, but in the must, well before the fermentation starts, by hydrolysis of the fruits pectin by dint of an enzyme: pectin methylesterase present in the fruits. Very ripe fruits contain already some methanol (as well as ethanol). ]

Methanol detecting in pure alcohol

Two methods can be used for methanol measuring in a solution containing also ethanol. The first one is a colorimetric dosage. The second method necessitates the use of a gas chromatograph, a little available device. We will not speak about it here.

1) Method using fuchsine

Source: Proost number 8, p. 27.

2) Methanol seeking as an aldehyde

A very detailed method, using chromotropic acid, is given here (in French): Recueil international des méthodes d'analyses OIV Méthanol.

Maximal authorized amount

According to the country and the beverage, the tolerated maximal amount can vary. Nevertheless, European Union has the good idea to match the concerned legislation.

Table of the maximal methanol amounts authorized in the European Union.

Alcoholg/hL pure methanol
Alcohol from agricultural origin50
Wine brandy200
Brandy from grape marc1000
Brandy from fruit marc1500
Fruit brandy1000
Fruit brandy (plum, mirabelle, quetsche, apple, pear, raspberry, blackberry)1200
Fruit brandy (Williams pear, red currant, black currant, rowan berry, elderberry)1350
Brandy from cider and perry1000

Source: Internet site Wikignôle.


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