2-isopropyl-3-methoxypyrazine

Technical specification

Assessment

The best way to detect 2-isopropyl-3-methoxypyrazine in water 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

6.0 ng per casule

Threshold

The flavour threshold of 2-isopropyl-3-methoxypyrazine in water is 2 ng / l.

Origins

2-Isopropyl-3-methoxypyrazine is formed by Actinobacteria in lakes, reservoirs and water distribution systems. It may occur in water in admixture with other methoxypyrazines.

Importance

2-Isopropyl-3-methoxypyrazine imparts a potent off-flavour with a very low flavour threshold. It gives an unpleasant mouldy / musty note to water which is reminiscent of potato skins or dug soil.

CAS registry number

The CAS registry number of 2-isopropyl-3-methoxypyrazine is 25773-40-4.

Other names

• bean pyrazine
• 2-methoxy-3-(1-methyl ethyl) pyrazine
• 2-methoxy-3-isopropyl pyrazine
• 2-methoxy-3-propan-2-ylpyrazine
• 2-isopropyl-3-methoxypyrazine
• 3-isopropyl-2-methoxypyrazine

Remarks

2-Isopropyl-3-methoxypyrazine is usually associated with surface water abstraction. Its formation can be influenced by weather conditions leading to concentration of organic materials in the water and growth of microorganisms.

Threshold distribution

Capsules per pot

10