Green Bell Pepper Characteristics (IBMP)

IBMP (3-Isobutyl-2-methoxypyrazine) is the main compound responsible for the “green bell pepper” aroma in wine.  In a white wine such as Sauvignon Blanc, the compound adds an often desired “grassy” character. In red wines however, this flavor is largely unpopular. Excessive IBMP levels in red wines, typically Cabernets or Cabernet-based blends, can lead to disappointing ratings and mixed success in the marketplace. 

The “green bell pepper” flavor in wine depends primarily on IBMP levels in harvested grapes. Once grapes have been picked, IBMP levels are not easily altered by standard winemaking processes.

Testing and Application

The intensity of “green bell pepper/grassy” characters in wines can be predicted by measuring IBMP in grapes right before harvest. Grape screening of IBMP helps identify “problem” vineyards or blocks. 

Since IBMP decreases during grape maturation, monitoring IBMP levels throughout ripening is a unique tool for assessing “aromatic maturity” in Sauvignon Blanc and Cabernet grapes. It allows targeting harvest dates based on desired aroma characteristics.

IBMP levels in grapes can often be effectively manipulated long before harvest. Vineyard management decisions such as trellis types, early leaf removal, fertilization and water availability are well known to impact IBMP levels in grapes. Monitoring IBMP from the early stages of the ripening process can greatly improve fruit quality from underperforming vineyards. Once the kinetics of IBMP accumulation and degradation in specific sites are understood, viticultural practices can be modified accordingly.

The IBMP potential of grapes can be grossly underestimated from juice samples, making whole berries the preferred sample in most cases. Analyzing juice samples may be relevant in white winemaking, however.

ETS Labs offers precise IBMP testing and expert insights to help you make smarter harvest and vineyard management decisions. Contact us today to learn how our advanced analytical tools can support your goals—from grape to glass.

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ETS Laboratories Winemaking Green Bell Pepper