Ch. 14: Maturation Flashcards
Micro-oxygenation
A technique to gradually introduce oxygen to wine without the need for barrel aging. Hence, it is a cheaper alternative.
It involves bubbling oxygen through the wine and is thought to increase color stability and intensity, soften tanning, improve texture, and decrease unripe, herbaceous flavors. If used with oak alternatives (such as chips or staves), it can help integrate the oak flavor more smoothly. The rate of control of oxygen exposure can be controlled much more tightly than in oak barrels, and can happen more quickly.
It is increasingly used for premium wine production as well as inexpensive or mid-priced wines.
Barriques
Small wooden vessels (225 l) used for maturing wine. Because the surface area is large compared to the proportion of liquid, the extraction of wood compounds is greater.
European oak
In comparison to American oak, European oak tends to impart more tannins and extract more subtle flavors and aromas. It is more expensive due to the production process.
Both European and American oak are high in vanillin, which imparts a vanilla flavor to the wine
American oak
American oak tends to extract more aromas and flavors than European, and has higher levels of lactones, which impart coconut flavors. It grows significantly quicker than European oak and can produce more barrels from the same amount of oak.
Both European and American oak are high in vanillin, which imparts a vanilla flavor to the wine
Oak seasoning
Before the oak staves are shaped onto a barrel, they need to be seasoned, which usually takes place outdoors and takes 2-3 years. Seasoning the wood reduces its humidity and bitter flavors, and increases other aroma compounds, such as clove.
Toasting
The heating of the staves so that they can be bent into shape for barrel production. The length and temperature of heat exposure is referred to as toasting, and barrels are typically classified into light, medium, or heavy.
Toasting contributes notes of caramel, spice, roasted nuts, char and smoke.
Oak chips
An alternative to aging wine in oak which is often used for more inexpensive or mid-priced wines because it is cheaper than oak barrels, less labor intensive, and provides the ability to fine-tune the style.
Oak chips are placed permeable sack and left to soak in the wine.
Oak staves
An alternative to aging wine in oak which is often used for more inexpensive or mid-priced wines because it is cheaper than oak barrels, less labor intensive, and provides the ability to fine-tune the style.
Oak staves are attached to the inside of a stainless steel or concrete vessel, or floated in the wine.
Lees
The sediment that settles at the bottom of a wine barrel. It is made up of dead yeast, dying yeast and bacteria, grape fragments, tannins, and nutrients.
In white wine, they produce aromas such as yogurt, dough, biscuit, or toast.
Lees aging helps in the stabilization of white wine against proteins that can cause hazes.
They help protect against oxygen, aiding in a slow, controlled oxidation during maturation, and reducing the need for SO2 at this time.
If the lees is too thick, it can produce volatile, reductive, sulfur-like compounds. This can add to complexity, but may contribute to faulty aromas, such as rotten eggs (reduction).
Lees provides nutrients for microbes, so can assist in the growth of lactic acid bacteria for MLF, but can also encourage the growth of spoilage organisms such as Brettanomyces.
Gross lees
Sediment that forms quickly after the end of fermentation made up of larger, heavier particles. Removed by racking.
Fine lees
Smaller lees particles that settle more slowly. Levels are managed by racking.
Autolysis
When yeast cells die and break down after fermentation, releasing compounds that contribute to the flavor, body, and texture of wine.
It imparts characteristics in a wine such as richness and creaminess, softer tannins, less astringency.
Racking
The process of transferring wine from one vessel to another, with the aim of removing sedimentation.
The wine is removed from the original vessel through a valve near the bottom, and pumped into a new, clean vessel.
Racking can be oxidative, so winemakers may enhance oxidation by splashing the wine into the new container. For wine styles that require protection from oxidation, like aromatic wines, oxidation can be controlled by pumping the wine through a hose using pressure from inert gas.
Blending
Mixing together two or more batches of wine. It can take place at any time during the winemaking process, but usually takes place just before finishing and packaging.
Blending may involve combining wines:
* from different grape varieties or clones
* from different locations
* from different grape growers or business that sell grapes, must, or wine
* from different vintages
* that have been treated differently in the winery (oak, stainless)
* From different vessels (small oak barrels)
Several key reasons for blending include:
* creating balance (e.g. Merlot, Cab)
* consistency (Sherry, NV Sparkling)
* style (house style, premium)
* complexity (two or more parcels of wine can lead to a greater range of flavors)
* minimize faults (volitile acidity)
* increase volume
* price (chardonnay mixed with more inexpensive varietals)
