This research investigated yeast populations and diversity during pre-fermentation cold maceration and alcoholic fermentation of Vitis vinifera L. cv. Pinot noir grapes from a commercial vineyard (Dayton, OR). Fermentations were conducted at the Oregon State University research winery in 100 L tanks while grapes from the same vineyard lot were...
Cold soaking is a technique used during red winemaking to alter the aroma, flavor, and phenolic content of a wine. However, cold soaking does not come without risk, as this process can result in the production of spoilage compounds such as acetic acid and ethyl acetate if excessive growth of...
Pre-fermentation cold soak is a winemaking technique used to alter the color, mouthfeel, and aroma of red wine. While it is still debated what impact cold soak has on these wine quality parameters, current thoughts are that resident yeast populations found in fresh grape must play a role in altering...
One of the most common problems in wine production is the formation of hydrogen sulfide (H₂S) and other volatile sulfur compounds (VSCs), which can mask positive aromas at low concentrations and result in unpleasant aromas such as rotten egg, cabbage, garlic, and rubber at higher concentrations. Despite the large body...
Malolactic fermentation (MLF) is an important step in the production of wines and is commonly performed in red or cool climate wines to reduce acidity. In this study the impact of MLF on red wine color and the ability of Oenococcus oeni to degrade compounds important to the development of...
Malolactic fermentation (MLF) is important in the production of wines as it reduces acidity through the conversion of malic acid to lactic acid. However, successful MLF can be difficult to achieve due to yeast antagonism of the bacterium responsible for
the secondary fermentation, Oenococcus oeni. In particular, yeast produced sulfur...
The human senses can be used as analytical tools to evaluate many different aspects of our daily lives. The use of our senses through organoleptic methods offers unique and powerful insights into the characteristics of different stimuli. Due to the unique function of the different sensory organs we use to...
Wine is particularly vulnerable to infection by Brettanomyces bruxellensis during or shortly after malolactic fermentation (MLF). While different methods and techniques enable winemakers to prevent wine spoilage due to this organism, no single intervention is universally sufficient. Moreover application of sulfur dioxide, the most commonly used of these methods, is...
The growth of Brettanomyces bruxellensis is a major cause of wine spoilage due tothe production of the volatile phenols 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG), derivatives of p-coumaric acid and ferulic acid. During the winemaking process,some microorganisms can impact the concentration of the 4-EP precursors pcoumaricand coutaric acid (tartaric acid-esterified p-coumaric...
This research investigated the effects of Pediococcus spp. on Oregon Pinot noir wines. Pediococcus (P. parvulus (7), P. damnosus (1), P. inopinatus (1)) isolated from Oregon and Washington state wines demonstrated differences in their susceptibility to SO₂ with some isolates growing well in model media at 0.4 mg/L molecular SO₂....