2-isobutyl-3-methoxypyrazine

Technical specification

Assessment

Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary.

Amount of flavour per capsule

50 ng

Threshold

10 - 16 ng / l in wine

Origins

Contributed by certain grapes as a varietal character. Higher levels of methoxypyrazines are associated with under-ripe grapes and the presence of vine stem material during extraction of juice.

Importance

At low levels imparts a desirable herbaceous, bell pepper, varietal character. Too much suggests insufficient maturity of the grapes. It is regarded as an off-flavour at higher concentrations or in some wine styles. Isobutyl methoxypyrazine is one of several methoxypyrazines found in grapes and wine.

CAS registry number

24683-00-9

Other names

• 2-methoxy-3-(2-methylpropyl)pyrazine
• isobutyl methoxypyrazine
• 3-isobutyl-2-methoxypyrazine
• galbanum pyrazine
• 2- methoxy-3-(2-methyl propyl) pyrazine
• 2-methoxy-3-(2-methylpropyl)pyrazine
• 2-methoxy-3-isobutyl pyrazine
• 2-2-methyl propyl-3-methoxypyrazine

Remarks

Methoxypyrazines have remarkably low flavour thresholds. They represent a varietal characteristic in Sauvignon Blanc, Cabernet Sauvignon, Cabernet Franc and, sometimes, Merlot. Regarded as a spoilage characteristic in red Bordeaux wines.

Threshold distribution