Search: aroma transfer

This simple descriptive analysis provides a method for articulately communicating sensory attributes. The method can be utilized to formulate a list of attributes for the profile test. The list of attributes must then be statistically corroborated and reference samples employed to ensure that all of the testers identify the same reference substance for each of the given attributes (e.g., rancid butter, sweaty = reference substance butyric acid).

A joint project in 2005 was organized by industry partners Hopsteiner, HVG and Johann Barth & Sohn along with the Central Marketing Organization of the German Agricultural Industries (CMA) and became known as the CMA scheme. This objective of this tasting scheme is to determine hop-related factors influencing the sensory analysis of beer.

First of all, the intensity and quality of the hop aroma and flavor are evaluated in their entirety according to a ten-point scale with 0 as unpleasant and 10 as very good/very pleasant. Then, the intensities of individual characteristics are also ranked on a ten-point scale, with 0 as imperceptible and 10 as very intense. For beer with a pronounced hop aroma, the following descriptors have become established in recent decades: fruity, floral, citrus, green-grassy and hop-spicy. These are available for specific training in the evaluation of hop oil fractions. Distinctive aromas detected by tasters can be described in the space provided. In order to characterize the overall impact of the hops, the bitterness is also evaluated sensorially. Both the intensity and the quality/harmony are evaluated on a ten-point scale, with 0 rated as completely lacking balance and 10 as very harmonious.

The mean values of the intensity of the hop aroma and flavor as well as the intensity of the bitterness are given on the score sheet (i.e., the sum of the scores divided by the number of tasters). The mean value of each aroma characteristic is reproduced as a spider diagram. The individual values should be checked for outliers prior to the calculating the mean. Since quality assessments are subjective by nature, the mean values can only be of limited value. However, they can be beneficial in determining whether any distinctive aroma or flavor characteristics were judged by the majority to be pleasant or unpleasant. The same applies to assessing the quality of the bitterness. 

The aroma compounds in hops are driven out through steam distillation and are captured in a special apparatus. The determination is carried out through reading the volume transferred into the apparatus.

An increasing number of products with unique aroma formulations or very intense flavors are now being packaged in returnable PET bottles. This places new demands on the manufacturers of PET bottles and beverage producers as well as filling and packaging facilities. These bottles require more complicated cleaning procedures due to their lower heat tolerance, which in turn increases the likelihood of transferring odoriferous substances from one product to another. This phenomenon is universally referred to as the “carry-over” effect.

One source for this effect is the misuse of refillable PET bottles by customers who utilize them for storing highly odoriferous substances or chemicals. However, this effect is not limited to substances from previously used bottles but may also be attributable to adsorptive substances used in the materials of the packaging itself (seals, etc.), to inadequate cleaning or to any existing dead space in tanks, aggregates or piping systems. All of these factors are potential sources for the carryover of undesirable aroma components. Above all, filling a container with a product containing a less pronounced aroma than that of the preceding one can result in carry-over. 

Kaltner (2000) developed a score sheet for assessing beers with a strong hop flavor, which on one hand is based on the DLG quality assessment of beer (refer to S.590.53.700 Einzelprobenprüfung zur Qualitätskontrolle von Bier - DLG-Prüfschema für Bier). The criteria aroma, flavor, fullness, liveliness and bitterness are evaluated using a five-point scale in half-point steps, where 5 denotes a pure attribute and 1 indicates major faults. On the other hand, the quality and distinction of the hop aroma and bitterness are assessed. The aroma and flavor of the hop impression are also distinguished. The evaluation is also based on a five-point scale with an intensity of 5 corresponding to the attribute “perfume-like” and 1 to “not perceptible”. Under “quality of the hop aroma” a score of 5 is considered “pleasant” and 1 “unpleasant”. Additionally, the score sheet provides space for describing the sensory impression of the appeal of a particular hop note. The intensity of the bitterness is also evaluated on a five-point scale, and in this case, 5 denotes a very strong impression, and 1 a very weak one.

The appeal of the bitterness has been plotted on a graph and is expressed using the following terms:

• rapidly diminishing (low intensity)

• fine, harmonious (moderate intensity and pleasantly lingering)

• hard (high intensity and fleeting)

• lingering (high intensity and persistently lingering)

One of the fundamental prerequisites for a properly structured sensory evaluation of beverages is training members of the tasting panel.