Tannins in Winemaking have 4 points of interest
Precipitation of proteins or “sacrificial” effect
Grape proteins combine and precipitate with phenolic compounds. This precipitation reduces the natural amount of grape tannins and can be limited due to the “sacrificial” effect: by using extra tannins that will combine specifically to the proteins. This “sacrificial” effect can be evaluated in the laboratory by measuring the tannins reactivity with a reference protein such as BSA.
TANIN VR SUPRA® provides a strong protective effect for natural grape phenolic compounds. Its reactivity is 5 times superior than other vinification tannins.
The antioxidant effect
The use of tannins has always been linked to their ability to moderate the effects of oxygen. They have antioxidant properties and protect oxidizable compounds. It has been proven that 30 g/hL (300 ppm) of TANIN VR SUPRA® added in increments during fermentation reduces the amount of dissolved O2 three-fold in must at the beginning of the fermentation which limits the oxidation risk of easily oxidizable compounds.
The inhibition of laccase activity
The presence of Botrytis is most often accompanied by a polyphenol oxidase (laccase), which is highly damaging. Due to the precipitation of proteins (the sacrificial effect) and the rapid consumption of O2 by the tannins (antioxidant effect), TANIN VR SUPRA® ensures an effective reduction of these harmful oxidase activities.
The co-pigmentation effect
The phenomenon of co-pigmentation results from the molecular association of coloured pigments such as anthocyanins with other more or less coloured pigments (tannins, phenolic acids…) leading to complexes (co-pigments) having a colour intensity greater than that of the coloured pigment alone. Co-pigmentation seems to play an important role in the colour of young wines. Red wines that are the richest in co-pigments present a more intense colour from the earliest stages of winemaking and it also seems more durable over time. TANIN VR SUPRA® and TANIN VR COLOR® are two tannins with good co-pigmentation ability.
Condensation effect (stabilization of color)
Acetaldehyde molecules are involved in stabilising simple coloured phenolic structures through reactions leading to more complex molecules. The efficiency of the tannin/anthocyanin bond via an acetaldehyde bridge can be simply demonstrated by saturating a tannin solution with acetaldehyde and then observing the evolution of turbidity over time. A benchmarking study has been done with many tannins available on the market using this method: TANIN VR COLOR® was more than 100 times more reactive than the closest competitor product.
Specific case: lack of phenolic maturity
When harvest is not at optimal phenolic ripeness, the qualities of TANIN VR SUPRA® and TANIN VR COLOR® are complementary.
Thanks to its remarkable “sacrificial” effect, TANIN VR SUPRA® helps protect the natural extractable grape tannins from precipitating with naturally occurring proteins, while TANIN VR COLOR® brings balance to the tannin/anthocyanin ratio and promotes the production of stable coloured compounds.
Whenever the vintage looks like a difficult one with challenges for grapes with optimal phenolic ripeness, the use of proper tannins, for example, TANIN VR SUPRA® and TANIN VR COLOR® will be a key point to successful vinifications.
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|Condensation effect (Colour stabilisation)||*||*****|
TANIN VR SUPRA® is added to the must after the crusher or during the first pump over (if no evidence of Botrytis) (20 – 80 g/hL / 200 – 800 ppm according to the sanitary state of the harvest). TANIN VR COLOR® is added during the first third of the alcoholic fermentation during the colour extraction phase at 10 to 30 g/hL (100 – 300 ppm).