► The Affects of Temperature in Wine

Aroma, flavor, color and structure creation and preservation is paramount to Vinology (the science of wine-making). Fine wine is extremely sensitive to temperature changes during production and storage that would lead to either undesirable “spoilage” or desirable “aging.”

Higher temperatures lead to wine "spoilage." Unchecked fermentation, due to elevated temperatures, works to destroy the wine by "cooking" it, resulting in foul odors and off-flavors. When temperatures vary the wine expands (when it is warm) and contracts (when it is cool) and the corks may push out or pull in accordingly, allowing a tiny amount of oxygen into the bottle. If enough oxygen enters the bottle, over time, it will spoil the wine. Excessive fermentation also “matures” the wine faster and causes the wine to achieve optimum quality before the consumer is ready for it.

Precisely controlled temperatures result in wine "aging," the beneficial maturation of the wine which improves the wine characters (acidity, tannins and alcohol level) over time. For stored or cellared wine, cooler temperature leads to slower aging and greater the ultimate character complexity.

► Temperature Conditions Critical to Fine Wine

  • “Must” Cooling Temperature

After the grapes are converted to “must,” a mixture of juice, skin and seeds, the must is pumped through “must chillers” to reduce the temperature to about 53.6°F (12°C).

  • General Fermentation Temperature

Temperature control is necessary to promote yeast growth and to extract the flavors and colors from the skins (if skins are fermented). The best temperature for yeast growth is about 77°F or 25°C. The lower the temperature level, the longer the fermentation process.

  • White Wines Fermentation Temperature

For white wines, wine-making juice is pressed as unfermented must. After inoculating with a selected yeast culture, the must is allowed to ferment for from 2 to 45 days at a temperature usually between 45° and 65° F/7° to18.3°C. The lower the temperature, the longer the fermentation continues and the more fruitiness in the resulting wine.

  • Red Wines Fermentation Temperature

For most red wines, winemakers crush, sulphite and inoculate the grapes and allow the juice to ferment in contact with the skins and pulp for 2 to 5 days at temperatures between 70° and 80° F/21.1°C to 26.7°C (pinot noir is often allowed to go to 95° F/35°C). During this initial period, color is extracted from the skins as more sugar is converted to ethanol. When the fermentation has begun or completed, reds are pressed for wine-making juice.

  • Yeast Re-hydration Temperature

Re-hydrate wine-making yeast for 15 minutes in warm, room temperature water (under
100°F/37.8°F).

  • Wine Processing Temperature

Cold stabilization removes excess tartaric acid that, if untreated, might later form potassium bitartrate crystals, which can show up in wine bottles or on corks. Cold stabilization is accomplished by allowing the wine to warm up to "room temperature" and then chilling it down to about 40°F/4.4°C.

  • Wine Aging/Storage Temperature

Constant temperature is the key to wine storage. By causing the wine inside the bottle to expand and contract, swings in temperature rapidly ruin bottled wine. Ideal cellar temperature is 45 - 55°F (7 - 13°C) and kept constant. At lower temperatures, maturation is slowed, though more complexity is allowed to develop. Wine could be safely stored to within a degree or two of freezing, but it would take decades to develop. On the other hand, wines can be stored at up to 68°F/20°C, where they will mature quite rapidly. Higher temperatures than this will quickly damage the wine. Some degree of humidity is beneficial for long term wine storage, to ensure that the exposed end of the cork does not dry out and allow oxygen into the bottle. Beware of air conditioners, as they actually suck moisture out of the air. Ideally, relative humidity should be between 60 - 75%. Humidity higher than that encourages mould growth in the storage area (not to mention label deterioration!).

The new DeltaTRAK Waterproof Dishwasher Thermometer Kit (P/N: 12211) is designed specifically for checking temperatures inside commercial dishwashers. This kit comes with an accurate, application-proven Waterproof Lollipop Probe Digital Thermometer (P/N: 11036) and an improved waterproof, flexible plastic protective Heat Shield (P/N: 12208).

The Waterproof Lollipop Probe Thermometer has minimum and maximum memory features and records the lowest and highest temperature, between -58°F to 392°F (-50°C to 200°C) with ±1°F (±0.5°C), measured since the last reset. This instrument is ideal for verifying dishwasher and holding temperatures for HACCP compliance (see Table 1). The Waterproof Lollipop Probe Thermometer is NIST Traceable and CE marked.

The new plastic protective Heat Shield is made from temperature-stable, flexible plastic material and is colored red or easy identification and location both inside and outside dishwashers. It protects the Waterproof Lollipop Probe Thermometer's LCD display from overheating and turning black when the thermometer is used in consecutive dishwashing cycles.

Together the Waterproof Lollipop Probe Thermometer and the new plastic protective Heat Shield provide easy and long-lasting temperature measurement in HACCP-conforming dishwashing and holding applications.

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