During the winemaking process, colour extraction occurs when the grape skins are in contact with the must. The longer the skins are in contact with the juice, the more pigments will be extracted. Ethanol production during alcoholic fermentation will help to extract tannins that will impart not only the wine structure but also the colour stability, thanks to the formation of derived pigments.
Well, that’s the basic logic. However, there are more things to consider. At Oenobrands, we like keeping things simple, and here we remind you of the basics of why to use enzymatic preparations for the extraction of colour from grapes.
The colour of red wine comes from the anthocyanins, a sub-group of polyphenols, present in the grape skins. There are several extraction methods used in winemaking to extract aromas, colours, and tannins from grapes. The use of any technique in winemaking varies depending on the desired style of wine and the grape varieties being used.
The traditional maceration involves keeping the grapes in contact with the must for a specific period, ranging from a few days to several weeks. The maceration process can be conducted at different temperatures, with regular physical operations to promote extraction. The alcoholic fermentation happens partly or completely during maceration.
Winemakers can operate a cold pre-fermentation maceration, also called cold soaking. Before fermentation, grapes are chilled between 8 °C and 12 °C for many days. This helps mostly to enhance the aromatic characteristics and the red hue stability of the colour, limiting the action of an oxidative enzyme named PPO.
Heat treatments of the grapes can be done as well, and they involve subjecting the grapes to elevated temperatures for a specific duration before the winemaking process begins. Whether it is thermovinification or flash-détente (see section heat-treatments of grapes for more specific details).
Winemakers use various techniques during maceration to maximise the extraction of desirable elements from the grape skins, such as colour (anthocyanins), aroma compounds, and tannins, on top of managing well the alcoholic fermentation.
Reminders:
Enzyme preparations are commonly employed in combination with other maceration methods and are added to grapes to facilitate colour extraction. Pectolytic enzymes work by breaking down pectic compounds that hold the skin cells together, thereby promoting the release of anthocyanins into the must, but side activities such as hemicellulase and cellulase are compulsory to better degrade the skin grape cell wall and fasten and improve the phenolic compound extraction.
We know that higher temperatures, indirectly a lower pH (more a matter of colour intensity due to the different forms of anthocyanins depending on the pH), and higher alcohol concentrations can increase the rate of extraction. With enzyme preparations, you can go to another level. They can be used at various stages of red winemaking, such as pre-fermentation maceration or during fermentation when vatting.
In collaboration with dsm-firmenich, Oenobrands has developed a complete portfolio of Rapidase red wine enzymes, adapted for different red wine styles, winemaking processes, ripeness levels, and various commercial decisions.
Grape skin cell walls are a natural barrier to polyphenol diffusion during red wine maceration. Pectinase enzymes with cellulase and hemicellulase side activities (what are called maceration enzymes), breaking down the cell walls of grape skin, facilitate the release of desired compounds such as anthocyanic pigments, tannins, and aromas into the must. This increased diffusion of phenolics such as anthocyanins is done because of the degradation of the cell wall’s polysaccharide structures such as pectin, hemicellulose, and cellulose.
When using pectolytic enzyme preparation, you can expect the following results:
Yes, because the maceration enzymes will help facilitate operations during maceration and increase the diffusion of colour, structure, and aromatic compounds in the juice. However, we must not believe in miracles and rethink the context: we must think about the choice of its enzyme, or rather, its enzymatic formulation, according to the grape variety and its type of vinification. At Oenobrands, we offer you different enzyme preparations for red application with various compositions and activities. So depending on what you want to do and get, we can guide you in your choice by knowing the grape variety, desired wine style, maceration time, and other winemaking considerations.
See here the example of Rapidase Fast Color for winemakers doing short maceration, meaning 3 to 6 days of maceration and fermentation. This liquid enzyme is ideal to avoid greenness due to the maceration of unripe grapes or to help when winery capacity is limited. Rapidase Fast Color is also indicated for the maceration of aromatic red grapes.
No, the Rapidase enzymes do not change any oenological parameters of the juice or the wine.
As an example, see here our study about Rapidase Extra Color and Rapidase Extra Fruit on parameters such as pH, total tartaric acidity, potassium, polyphenols, and colour in a typical Tempranillo winemaking process at VITEC (Falset, Spain).
The test was done on tempranillo grapes (DO La Rioja), which were destemmed, crushed, and vatted in stainless steel tanks per 50 Kg of homogenous batches. Rapidase Extra Color or Extra Fruit were added at 3 g/100 Kg, and fermentation was initiated with an inoculation of 25 g/hL of Legacy NT 202. The maceration temperature was 24 °C, and pump-overs were done daily. Each maceration tank was drained and squeezed every four days. After 12 days, the wines were drained and pressed.
The two enzymes tested had no negative impact on the total acidity or pH of wines, especially when short maceration times were applied. Potassium concentrations increased after 12 days of maceration in the presence of these enzymes, but this didn’t result in a significant difference in pH or acidity. A higher extraction of organic acids could explain this apparent contradiction.
Moreover, after 12 days of maceration, the TPI values and tannin content of the wines treated with enzymes were greater than those of the control wines. This enhanced polyphenol content logically resulted in richer, more colourful, and better structured wines when the maceration enzymes Rapidase Extra Color and Rapidase Extra Fruit were employed.
The choice of an enzyme preparation over another one is also linked to the quality of the red grapes and the harvest conditions. By adjusting maceration times and techniques, using appropriate enzyme preparations, and controlling fermentation temperatures, winemakers can adapt colour extraction.
Let’s review what influences the matrix when harvesting:
Our recommendation is to consider:
With a highly qualified team of experts in many fields, Oenobrands strives to offer winemakers’ novel and scientifically sound solutions, as well as to highlight the positive synergies between its products.
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