Today, every ambitious winemaker or brewer knows: temperatures play an important role in the production of wines, beers, and alcoholic beverages of all kinds. And fermentation is where the final beverage is born. Gone are the days when you simply placed a loose water hose or wet towels on your fermentation tanks. Because correctly adjusted temperatures ensure the quality of the products; too high temperatures, however, can impair them or even cause the product to “spoil”. Today, market-ready quality can only be achieved with temperature-controlled processes. The key to this is proper temperature management during the production process. However, for many, the full meaning of this has remained in the background.
First off: It’s impossible without cooling – but cooling alone is not enough
Some producers believe they only need to use a water hose or a cooling coil, and the basic prerequisite for a good fermentation process would already be met. This view is short-sighted. Precise temperatures at the various stages of fermentation are crucial – this includes the storage and preparation phase of the must. Because only these enhance quality and open up possibilities to positively influence the character and taste of the products. Important: Continuously monitor fermentation activity; do not leave fermentation to chance, but guide it to its goal through proper fermentation management. If you don’t control fermentation, chance will dictate the outcome of your products.
Temperature-controlled Fermentation Management – What Does That Mean?
To bring wines, beers, or alcoholic beverages to their full potential, a holistic understanding of “fermentation management” is crucial. This encompasses the entire maturation process. For different process steps, there are different cooling requirements. Temperature control is the central control element, because temperature-based fermentation management means goal-oriented control. In this sense, the end product can be influenced at all process stages and optimized towards a desired goal: Higher temperatures can increase the complexity and aroma of the products, while lower ones promote fruitiness and acidity. As long as the fermentation and maturation phase continues, several hundred other chemical compounds can form in addition to alcohol, influencing the aroma, bouquet, and sensory taste. To produce uncompromising and reproducible quality, one needs, in addition to correctly designed cooling elements, professional fermentation control with highly precise temperature regulation.
The Various (Temperature) Maturation Stages (Fermentation Stages)
Simply put, the production process of alcoholic beverages can be divided into the following maturation or fermentation stages, often with different temperature profiles. Digital cooling systems with precise controls and regulations from LiquoSystems provide excellent service in this regard:
- Temperature-controlled Must Storage and Initial Fermentation Phase, if applicable with Yeast Preparation
- Temperature-controlled Fermentation (Main Fermentation Phase)
- If applicable, Temperature-controlled Second Fermentation for Red Wines (Malolactic Fermentation) or for Beers (for Carbonation)
- Temperature-controlled Post-Fermentation Phase (and also Storage Phase)
Even during storage, the must can be prepared and optimized for its intended purpose through targeted temperature application. For example, controlled fermentation management can increase the yield for the later aroma.
Generally, the following guideline values are used, from which professionals can, of course, deviate strategically in individual cases. The values are given here in grams of sugar per liter, as this unit of measurement is consistent across all our customers’ countries. Otherwise, in Germany, Switzerland, and Luxembourg, Oechsle (Oe) is used; in Austria and Hungary, Klosterneuburger; in France, Beaume; and in Spain, Brix.
Initial and Main Fermentation Phase: Ferment Swiftly, But Not Too Swiftly
Generally, the rule is: Ferment swiftly, but not too swiftly. A “stormy fermentation” is not the first choice. The initial fermentation phase lasts until the first 25 g/l of sugar are fermented. In the main fermentation phase, the sugar is fermented down to 50 g/l. Naturally, temperature control during the main fermentation phase is most crucial for the final character of the product. For beers, the temperatures for top-fermented beers are about 10 degrees below bottom-fermented beers. White wine, for example, is usually fermented between 15 to 18 degrees Celsius, red wine between 22 and 25 degrees. But what does ‘between’ mean? One degree more or less can make a big difference! And so producers with know-how, artistry, and highly precise cooling systems can “tease out” nuances. But even in the final fermentation phase, some effects can still be achieved if one truly understands how to leverage temperature control.
Depending on the maturation of the wines, a second fermentation (malolactic fermentation) follows for red wines. Here, malic acid is converted into the milder lactic acid. To specifically initiate this, the container may need to be warmed up in a controlled manner.
For all wines, the post-fermentation phase follows with many oenological possibilities. Temperature control also plays an important role in maintaining the desired storage temperatures. For example, to keep white wines sparkling with the remaining fermentation carbon dioxide.
Here is another example of different temperatures in the main fermentation of white wine and red wine
White wine first:
In cold fermentation (14 to 16 degrees), approximately 10 to 15 g/l of sugar are broken down per day, which corresponds to 4 to 5 Oe. In a controlled fermentation (18 to 20 degrees), approximately 20 to 30 g/l of sugar are broken down per day, i.e., 8 to 10 Oe.
Now for red wine:
In a controlled fermentation (20 to 23 degrees), approximately 20 to 30 g/l of sugar are broken down per day, i.e., 8 to 10 Oe. In warm fermentation (25 to 28 degrees), approximately 50 g/l of sugar or even more are broken down per day, i.e., at least 20 Oe.
Fermentation processes can vary so much, and temperature management must be equally diverse!
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