Winemaking Flashcards
Typical wine making process (after harvesting) - 5 steps
Crushing - splitting the grape skins to release some of the juice
Pressing - grapes are squeezed in a machine press to extract as much liquid as possible.
Sometimes done before (white wines) and sometimes after/mid fermentation (red and rose).
Alcoholic fermentation - process of creating alcohol with yeast. Yeast feeds on sugars to produce alcohol, C02, and heat. Alcohol in most dry wines is between 11.5 - 16%
Storage and maturation - storage prior to bottling. For most wines this period is less than a year. Some wines are stored for an extended period of time (maturation) to develop flavor and body. Maturation normally takes place in oak vessels.
Packaging - bottled.
Typical order/process for dry red winemaking (6 steps)
- Crushing
- alcoholic fermentation
- draining
- pressing
- storage or maturation
- packaging
How to extract color and tannin from black grapes (to make red wine)
Heat created by yeast during fermentation helps to extract color and tannin, but not without some help. Grape skins float to the top of the tank and create a ‘cap’.
2 methods are used to mix the skin with the rest of the liquid
- punching down - a plunger is used to push the cap down into the liquid
- pumping over - liquid from the bottom of the vessel is pumped through a hose and sprayed over the cap.
2 methods of making dry rose wines
- Short maceration - made from black grapes. Fermentation begins in the same way as red wines, but it is drained from the skins after only a few hours. Fermentation continues after that.
- Blending - made by blending a red wine with a white wine. Not permitted in many parts of europe
order/process for dry white wine
- crushing
- pressing
- alcoholic fermentation
- storage or maturation
- packaging
Generally made from white grapes, however can be made with black as long as the grapes are pressed very gently (so as not to extract color and tannin)
4 techniques for making sweet wines
- concentrated grape sugars - juice extracted from extra ripe grapes, botrytis/noble rot affected grapes, frozen grapes have such high levels of concentrated sugar that it’s impossible for the yeast to eat all the sugar before fermentation stops
- removing the yeast - filters with extremely small holes are used to filter the yeast out
- killing the yeast - most commonly by adding alcohol to the fermenting grape juice (fortification—fortified wines), raising the alcohol level to 15-20%, killing the yeast.
- adding sweetness to dry wine - the added sugar comes from grapes. Unfermented grape juice or highly concentrated grape juice. The other option is to blend a dry wine with a sweet wine.
temperature for alcoholic fermentation for red, rose, and white wines
- reds ferment at a higher temperature. From 20-32 degrees C
- rose, if made by short maceration, will ferment at the same temp as white wine once skin has been removed
- white wines are fermented at temperatures of 12-22 degrees C. At the lower end of this range fruitier aromas are produced.
different winery vessels
- stainless steel and concrete - can be used for both fermentation and storage. They are inert and do not add any flavor to the wine. Can also be made airtight, preventing oxygen from interacting with the wine and changing the flavors.
- oak - used to add flavors directly to a wine, or/and to allow flavors to evolve as a result of the interaction with oxygen during maturation.
- alternatives to oak barrel for flavor (because oak barrels are expensive) is to use
oak staves or oak chips in an inert vessel
what affects the flavor an oak barrel gives to wine
- The amount of flavor a barrel can give depends on how the barrel was produced, as well as age and size of barrel.
- Amount of heat and length of time used when forming the barrel can create ‘toasting’. This can produce sweet-spice and charred wood aromas and flavors.
- If the barrel is new and has not been used before, it will add significantly more flavor to the wine. Flavors such as vanilla, coconut, charred wood, and spice. These barrels are referred to as ‘new-oak’. Barrels that have been used 2-3 times, have very little flavor left to add. They are referred to as ‘old-oak’
- These barrels are not airtight. The interaction between the wine and oxygen can create flavors of caramel, dried fruit, and nut (hazelnut, almond, walnut). Oxygen also helps to soften the tannin in red wine. These changes occur more quickly in small barrels vs large because of the contact surface are.
malolactic conversion
takes place after the fermentation has finished, not through yeast, but through bacteria. The activity of the bacteria lowers the acidity in the wine and can give buttery flavors.
In red winemaking, this process almost always takes place and the buttery flavors are not noticeable.
In white winemaking, the winemaker has a choice. If they want to preserve the acidity and do not feel the wine will benefit from the buttery notes, they can stop the process (such as aromatic grape varieties, like riesling). Other grape varieties can benefit, such as certain styles of chardonnay.
what is lees
after fermentation, the yeast die and fall to the bottom of the vessel, forming a layer of dead cells referred to as ‘lees’.
If the winemaker chooses to keep the lees, it can be stirred up through maturation to increase the body of the wine and add extra flavor (biscuit, bread).
Typically avoided when making wines with aromatic grape varieties
when would a winemaker chose to blend
can take place at many stages in the winemaking. Important in defining and maintaining a style of wine. Consumers often expect some branded wines to taste the same, year to year, so a winemaker may chose to blend different wines each vintage to maintain that consistency.
Another reason would be to add complexity, by blending wines from different grape varieties, different vineyard locations, or made by different techniques.
what happens during bottle maturation
Once in bottle, most wines do not improve. Their fruit flavors start to fade and are replaced with vegetal notes.
Those that are able to improve over several years (sometimes decades) will often have high acidity, sugar, or tannins. Wines that mature in bottle need to have sufficient concentration of flavors that can evolve in a positive way and add complexity. Fresh fruit flavors turn to dried fruits, and other complex flavors such as mushrooms and leather develop.
Changes to white wine: color will change from lemon to gold to amber. Tertiary characteristics, such as dried apricot, honey, nut, and spice can develop.
Changes to red wine: color will change from ruby, to garnet, to tawny, and will become paler in intensity. Tannins will soften, tertiary characteristics such as fig, prune, meat and wet leaves will develop. Deposits can form in the bottles (will need to be decanted before serving)
What does a wine need to age?
- Flavour concentration
- Flavors that can develop in a positive way
- High acid, tannin, or sugar
