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Volatile aroma compounds are driven out of the sample through steam distillation. The ethanolic distillate is saturated with NaCl. Potassium hydrogen sulfite is added to separate carbonyl groups that might interfere with the analysis. The extraction of the aroma compounds is performed by shaking out with dichloromethane and the phases separated by centrifuging.

Determination of the moisture content of barley is carried out according to ISO 712, 2009, i.e., milled barley is dried at a defined temperature within a set time period in an electrically heated air-drying oven.

The moisture content is calculated through the difference in mass prior to and after drying.

Barley with moisture contents above 17 % must be pre-dried as whole kernels prior to analysis. This method is not suitable for malt.

The sample is heated directly on the weighing pan in the drying chamber using microwaves. The water evaporates and is removed by a compressor. In order to avoid disturbing the weighing process as little as possible, the sample is protected from the flow of gas by a porous cover. The change in weight is measured directly; after a constant weight is reached, it is evaluated.

With microwave-vacuum drying, the vaporization temperature is lowered, resulting in a more gentle drying process. Additionally, the samples are under constant rotation to prevent degradation and burning of the sample.

Terms

Aroma:
Aroma represents the overall sensory impression encompassed by the olfactory organs, some of which is perceived in the mouth and thus partly attributed to the sense of taste.

Flavor/Off-flavor:
For the sake of thoroughness, these two terms, which are defined in DIN 10950 part 2 Sensorische Prüfung, allgemeine Grundlagen, are mentioned here. According to definition put forth by DIN, flavor is defined as the “sum of olfactory, gustatory, temperature-related and/or trigeminal and tactile sensations in the mouth”. Off-flavors are sensory stimuli, which are perceived as unpleasant.

Odor:
Organoleptic properties perceived with the olfactory organ(s), whereby certain volatile substances are breathed in through the nose.

Flavour:
The overall sensory impression perceived through the sense of taste in the mouth, throat and nose. The sense of taste can be influenced by thermal or tactile stimuli, through pain or kinesthesia or any combination thereof. According to DIN, flavor is defined as the “sum of olfactory, gustatory, temperature-related and/or trigeminal and tactile sensations in the mouth”.

Mouthfeel:
Aside from the basic tastes, tactile stimuli – detected through haptic perception in the oral cavity – play a role in the sensory perception of comestibles as they are ingested. Tactile stimuli can be divided into the following:

• tactile (touch)

• kinesthetic (perception of weight, movement, resistance, etc.)

• trigeminal (pain)

• temperature-dependent

The term “mouthfeel” is often employed to describe haptic perception in the oral cavity. The following sensory attributes of beverages can be detected primarily by means of mouthfeel:

• viscosity, rheological properties

• liberation of gas, bubble formation, foaming (carbon dioxide)

• general after-effects in the mouth (refreshing, warming, thirst-quenching)

Aftertaste:
The sensory impression, which remains in the mouth, once a beverage has been swallowed. This is often employed as a criterion for the sensory evaluation of beverages.
An aftertaste described as “harmonious” provides incentive to continue drinking.

Orthonasal perception of odors:
Sensory perception commonly referred to as “smelling”. Odorants in the air enter the nasal cavity through the external nares, or nostrils, during the act of breathing. From there, the odorants are transported to the receptor cells where olfactory perception occurs.

Retronasal perception of odors:
Retronasal (lat. retro: “backwards, back”, nasal: “pertaining to the nose”) perception describes the transport of odorants from the oral cavity into the pharynx, then up through the internal nares and nasal cavity to the olfactory receptor cells. Odors are liberated through the mastication of food and beverages, thus providing olfactory (lat. olfacere: “to smell”) stimulus. The retronasal aroma profile of comestibles may differ from the orthonasal aroma profile owing to various factors (e.g. mastication or saliva).

Fullness:
Fullness is a kinesthetic sensation in the oral cavity, which – as it relates to beer – may range from “watery” to “satiating/excessive”. A frequently used synonym for fullness in beer is the term “body”.

Liveliness:
Liveliness as it pertains to beer is the tactile sensation in the oral cavity induced through the action of carbon dioxide, which may range from “flat/stale” to “gassy”.
A synonym often encountered for liveliness is “effervescence”.

The classic procedure performed using a drying oven is very time-consuming. Drying with infrared radiation significantly shortens the time required for drying, since the barley to be dried is immediately penetrated by the infrared radiation, which gives off a part of its energy, thereby heating the barley. With infrared drying, an adjustable heat source is connected to an electronic balance. The loss in mass during drying is continually recorded by the balance. The apparatus is equipped with a built-in microprocessor, which allows it to be programmed with data which was collected empirically with regard to optimal drying conditions.

Evaluation of the appearance of hop cones is performed through visual and manual inspection.