Monitoring Green Bell Pepper Characteristics in Grapes New Capabilities at ETS
ETS Laboratories offers the ability to measure IBMP (2-Isobutyl-3-methoxypyrazine) in grapes. IBMP is the main compound responsible for a “green bell pepper” aroma in wine. It is an extremely potent flavor compound, with reported sensory thresholds ranging from 6 to 15 ng/L (ppt) in wine-like solutions and wine. The ETS method utilizes GC/MS analysis with an IBMP isotopic analog as internal standard.
IBMP may be desirable in some wines like Sauvignon Blanc, favorably contributing its herbal/grassy character, but is often unpopular in red wines. Excessive IBMP can lead to disappointing ratings and affect success in the marketplace.
IBMP concentration in fruit is closely related to the sensory intensity of finished wine. IBMP can decrease quickly during maturation, but once grapes are picked, levels cannot be easily altered by standard winemaking techniques. Applications
- Vineyard comparisons and trials Climate and terroir can affect IBMP levels in grapes as can vineyard management decisions such as soil drainage, varieties and clones, row orientation, trellis system, irrigation, fertilization, vigor, grape thinning and leaf removal.
- Harvest decisions Changes in grape IBMP during maturation will directly influence final levels in wine and may be crucial in making picking decisions.
The harvest grape sample can be taken in the vineyard or directly from harvest containers. IBMP levels can vary between clusters and even between sun-exposed and shaded berries on same clusters. A good sampling program is essential to insure that the sample is representative. ETS studies indicated that 200-berries samples, as typically submitted for evaluation of grape maturity, should provide reliable results. This document is a compilation of information and views from various sources provided for the convenience of our clients. Information in this document is provided "as is" without warranty of any kind, either expressed or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and freedom from infringement. User assumes the entire risk as to the accuracy and the use of this document. This document may be copied and distributed subject to the following conditions: 1) All text must be copied without modification and all pages must be included; 2) All copies must contain ETS's copyright notice and any other notices provided therein; and 3) This document may not be distributed for profit. All trademarks are acknowledged. Copyright ETS Laboratories 2001-2013.