Structan finishing tannins assist in adding great mouthfeel, character and structure to your wine

Finishing Tannins

… adding oak tannins to assist in adding value and completing the winemaking process.

Structan has been developed as a finishing tannin using 150 year old French oak and 90 year old American Oak, the same raw material used for making barrels.

The same congeners found in a new oak barrel are found in Structan with substantially improved consistency and concentration, contributing to a more efficient and effective result when used in wine production.

Structan is a powerful natural stabilizer, colloidal integrator and structuring agent. When added in wine production, Structan improves the quality of the end product, imparts wood character and delivers a more balanced and refined wine.

The winemaking challenge

Oenological tannins are widely used in the wine industry to improve wine quality. The bulk of these are either delivered through alternate oak products such as chips, staves and powders or derived from grape seeds, gall nuts and other botanical sources.

Structan’s range of oenological tannins deliver the familiar depth, character, structure and mouthfeel as you would find in oak barrels. Structan is used to structure, develop and enhance the natural flavors and aromatics in your wine and bind to anthocyanins to improve color stability.

Strucan imparts the typical organoleptic senses usually derived from barrel maturation and is composed of Gallo-Ellagic tannins extracted from French and American Oak.

Structan can be added at fermentation to assist in the integration and structuring of the wine, imparting key wood notes. It can also be added later in the winemaking process to improve mid-pallet structure and softness. Structan has been shown to reduce off-aromas, improve clarification, inhibit laccase activity from Botrytis or rot, and serve as a potent anti-oxidant.

Benefits of Structan

Dosing Structan

  • Shake the container prior to opening

  • Measure out a quantity of Structan

  • Add Structan at Malolactic Fermentation for Red wine and Alcoholic Fermentation in White wine

  • Alternately dose in blending tanks

  • Ensure it is properly mixed

  • Carry out normal filtration

  • You are good to go !


Min 0.5
Max 1.5


Min 1.0
Max 3.0

Very small dosages of Structan are required, as our extract is already in a highly concentrated liquid form.

This makes measuring and adding really simple, no premixing or dissolving necessary.

Winemakers can fine tune the delivery of WineShield as they wish and deliver the exact output they require (dosing shown here is all in mL dosed in 1L of wine or at a ratio of #:1000)

Highly concentrated.

0 Gallons
of stabilised wine from only 1.3gal WineShield
0 Liters
of stabilised wine from only 5L of WineShield
0 Bottles
of stabilised wine from only 5L of WineShield

Frequently Asked Questions

Structan is a potent finishing tannin and wine structuring agent.

Structan comes in a concentrated liquid form and dosed into the wine at fermentation or in the blending tank pre filtration.

Structan is an entirely natural product. The OIV institute has officially approved the use of the product in wine and Stoak has completed full organic certification on all of it’s products.

Yes, internationally recognized laboratories in Europe and Australia have tested our extracts and observed reduction in oxidative actions by up to 77%

Structan has been used in the wine industry for over 3 years. Test results show no effect on pH or Proteins .

Yes it will work with your existing industry clarifiers. We recommend you continue to clarify in the same way you have in the past.

Structan is GRAS (Generally Recognised as Safe) approved as an additive.

Structan is a partial clarifier so it will not affect turbidity, we do however recommend you use your standard filtration process.

Structan  has been successfully used by winemakers to finish off their blending process, adding the optimum level of roundness, mouth feel and tannin profile for a successful vintage.

Structan works together with the flavor and aroma compounds, it assists in integrating, protecting and rounding them with a delicate balance of tannins and structure.