Isopropyl methoxypyrazine (IPMP) is a methoxypyrazine, a class of chemical compounds that produce odors. The odor is rather undesirable and is produced by the Asian lady beetle or by the actinomycete Streptomyces sp, and yeast, specifically Saccharomyces cerevisiae. Three highly odorous metabolites from an actinomycete: 2-Isopropyl-3-methoxy-pyrazine, methylisoborneol, and geosmin. Nancy N. Gerber, Journal of Chemical Ecology, Volume 3, Number 4, pp. 475-482, It can be detected by human taste at concentrations of as low as 2 nanograms per litre.
Presence in wine grapes The odor of IPMP tends to be undesirable in the case of certain wines.
Cabernet Sauvignon has high levels of methoxypyrazines.winepros.com.au Oxford Companion to Wine methoxypyrazines Oz Clarke Encyclopedia of Grapes pg 223 Harcourt Books 2001 Two methoxypyrazine compounds, 3-isobutyl-2-methoxypyrazine (IBMP) and 3-isopropyl-2-methoxypyrazine, are considered to be important determinants of green flavours in Sauvignon blanc wines.Marais, J., Hunter, J.J., & Haasbroek, P.D. (1999). Effect of microclimate, season and region on Sauvignon blanc grape composition and wine quality. South African Journal of Enology and Viticulture, 20, 19-30.
Presence in coffee IPMP is also an important flavour compound in coffee and is responsible for causing an off-taste called "potato taste" in East African coffee. The insects Antestiopsis are also implicated in causing the taste.
See also Alkylpyrazines
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