General Winemaking options Flashcards
Oxidation
Generally not good for fresh fruity wines. Many compounds like thiols in Sauvignon blanc break down with oxidation.
Sulfur dioxide
Strong anti oxidative effects
Anti oxidant
So2 property that only Tracy with oxygen very slowly.
Anti microbal
Property of so2 that Inhibits yeast and bacteria.
Bound so2
When so2 is added to must or wine it dissolves and some of it reacts with compounds in liquid.
Free so2
Proportion of so2 that is not bound.
Grape Transport
When grapes are transported to the winery. Vulnerable to oxygen and to ambient yeasts and acetic acid bacteria. Threats higher with higher temps. Black grapes less vulnerable due to phenolic compounds that have anti oxidative properties.
Grape Reception
Number of options possible depend on volume of grapes, hand or machine harvested and health of grape.
Chilling
If warm grapes arrive you might chill before crushing begins to reduce oxidation and to preserve fruit aromas.
Sorting
Can depend on quality of grapes. In poorer years, more sorting may be required. MOG needs to removed.
Optical Sorting
High tec/cost option that uses digital imaging and software technology to scan individual grapes. Machine scans 100 grape sample as a reference. Typically used for premium wines
Destemming
Works by a series of blades within a rotating drum that remove the grapes from the stems. Sometimes whites are not destemmed for high quality white wines.
Crushing
Application of sufficient pressure to the grapes to break the skins and release the juice, making it available for fermentation.
Must
Mixture of grape juice, pulp, skins seeds that come from the crusher
Pressing
In white winemaking, grapes are almost always pressed to extract the juice from the grapes to separate the skins. Red winemaking grapes are typically crushed before fermentation and pressed after the desired number of days on the skins at the end of fermentation.
Pneumatic Press
Air bag presses. Cylindrical cage with a bladder that runs down the side or middle. As the bladder is filled with air, the grapes are lightly pressed.
Basket Press
Vertical press or champagne press, basket is filled with grapes and pressure is applied from above. Juice runs through the gaps or holes in the sides of the basket and is collected by a tray at the bottom.
Horizontal Screw Press
Similar to basket mounted horizontally above rectangular draining tray. Less gentle than other types. Requires batch process (as with basket and pneumatic press)
Continuous Press
Allows grapes to be continually loaded into the press at is works by using a screw mechanism. Allows for quicker pressing of large volume of grapes. Best suite for high volume since it’s less gentle.
Must adjustments
Aim to create more balanced wine, esp if there has been a compromise in achieving optimum ripeness of sugars, acids, tannins and flavors.
Enrichment
Common in cooler climates to enciphered the must before or during fermentation to increase alchohol. Adding dry sugar, grape must, grape concentrate or rectified concentrated grape must
Chaptilisation
Adding dry sugar
Acidification
Can also be used to lower PH in wine. Is carried out by addition of tartaric acid Other options are adding citric acid, malic acid, lactic acid.
Deacidification
May be used in cooler climates. Carried by adding calcium carbonate (chalk) or potassium carbonate and it lowers acidity by the formation and precipitation of tartrates. Ion exchange a high tech option.
Yeast
Group of fungi that converts sugar into alchohol and affect the aroma flavor characteristics of wine
Saccharomyces cerevisiae
Common species of yeast used in winemaking. Can withstand the high acidity and increasing alcohol level of the must as it ferments. Reliably ferments must to dryness.
Ambient Yeast
AKA Wild yeast, present in the vineyard and winery. Can add complexity resulting from number of yeast species. Fermentation may start slowly. Can’t be consistent. Maytake longer to ferment
Cultured Yeast
AKA Commercial yeast are yeast strains that are selected in a lab and then grown in volumes for sale. Often Saccharomyces Cerevisiae is sold.
Malo conversion
Result of lactic acid bacteria converting malic acid into lactic acid and carbon dioxide. Produces heat and typcially happens after fermentation.
Reverse Osmosis
A method of enrichment by removing water through reverse osmosis. Used to increase the alchohol content.
