Posts

Showing posts from September, 2017

Ethanol evaporation from wine glasses can change wine’s sensory characteristics

Image
Image source: Shutterstock
The aim of this study was to measure ethanol evaporation rates in covered and uncovered glasses filled with wine, in order to determine if it can have an effect on the sensory properties of wines.
Project layout Trial 1: 2014 Cabernet Sauvignon wine (50 ml) was poured into standard XL5 wine glasses. One set was covered immediately, one set left uncovered with no direct airflow and one set uncovered with direct airflow from the laboratory’s air conditioner. Ethanol and density of the wines were measured at specific time intervals.
Trial 2: Two white wines, two red wines and two fortified wines were subjected to the same conditions as in trial 1. Ethanol concentration was measured before and after two hours.
Trial 3: the same wine from trial one was poured in three differently shaped glasses (50ml): XL5, sparkling wine and Riedel. A 100 ml XL5 was also included in the trial. Ethanol concentration was measured before and after two hours.
Sensory analysis was …

The effect of enzyme, tannin and mannoprotein additions on the sensory properties of Shiraz

Image
Image source: Shutterstock
By Karien O'Kennedy
The aim of the study was to investigate to what extent winemaking supplements can alter the sensory properties of Shiraz wines from grapes picked at lower sugar levels to more closely resemble wines from grapes from the same vineyard, picked at higher sugar levels.
Project layout - Shiraz grapes were harvested at two sugar levels: 23.9°Brix (A) and 27.7°Brix (B), from a commercial vineyard in McLaren Vale, Australia. - The wines were fermented with Lalvin EC 1118 at 28°C. - Harvest A wines underwent seven different treatments: control, cold soak, enzyme addition, enzyme + mannoprotein (MP) addition, tannin addition, tannin + MP and MP alone. Laffort products: Lafase HE Grand Cru, VR Supra + VR Color and Oenolees MP were use in the trial. Details of dosages and timing of addition can be obtained from the scientific publication. - Harvest B underwent no treatments and served as the control wine made from grapes with a high sugar level.…

Microvine: A new model to study grapevine growth and developmental patterns

Image
Image source: Shutterstock
Microvines were initially proposed as a plant model for genetics. The purpose of this study was to determine the suitability of microvines for characterising grapevine vegetative and reproductive growth and development patterns in response to elevated temperatures.
What is a microvine? A microvine is a natural mutant of Vitis vinifera. Its dwarf stature allows experiments to be performed under fully controlled environments in small growth chambers. Another unique feature is that it has a short generation cycle and flowers continuously, giving it advantages similar to that of an annual plant. Studies can be conducted much quicker since experiments are not limited to the perennial growth cycle.
Project layout - A series of experiments was performed in a greenhouse and in growth chambers under either standard or contrasting conditions for several weeks - Plant development was monitored and a number of physiological measurements were taken - Biochemical analysis …

Linking sensory properties and chemical composition of berries to wine

Image
Image source: Shutterstock
The objective of this study was to compare the sensory properties of Cabernet Sauvignon grapes with the sensory properties of the corresponding wines. Predicting wine style from tasting grapes is unverified and the study aimed to elucidate the relationship between the two parameters.
Project layout - Grapes were harvested between 23-25° Brix from eight locations across South Australia - Data was collected over two vintages - Wines were made according to a standardised protocol - Grapes and wines were evaluated by a trained sensory panel - Basic chemical parameters of grapes and wines were also measured
Results Berry sensory attributes did not consistently relate to wine style and profile whereas basic chemical measures of berries were a more reliable indication of wine sensory attributes. These measures include Brix, anthocyanins and chroma of grape homogenates. Further data collection will be necessary to determine if berry sensory attributes can consistently…