Natural structuring agent for developing wine character

Structan’s range of finishing tannins provide ultimate structure, complexity, balance and mouthfeel. Winemakers looking for the latest technology in oak extraction that is designed for ultimate ease in dosing, with no need for filtration, 100% natural and organic, now have access to a unique set of tools to structure, finish and perfect their wines.


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. Our extraction process is highly sequenced but time honoured and involves no chemicals or synthetic ingredients. It is for this reason all our products are 100% natural and organic certified, critical for Organic and sulphur free wines.


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.


The Structan range of finishing tannins cover the full spectrum of wine applications across red and white wine which are a blend of French and American oak, with the white wine expressing less colour and intensity as the red.

We have also formulated specific French and American extracts which deliver the key advantages of these two varietals:

French – focuses more on greater mid palate richness

American – delivers greater vanillin and odorous compounds, lending to a more aggressive mouth feel and aroma.


Aqueous tannins have been used in winemaking for many years. Typically these tannins are derived from green and fresh vegetative sources in many cases derived from grape products, in order to extract aqueous tannins the raw material needs to be macerated and heated to the point it breaks down, losing much of the essential character winemakers want in their end product.

Structan’s range of non-aqueous tannins are derived only from aged oak wood with the typical character, depth and profile that barrelling brings. Our extracts are all in liquid form but closer to the desired mouthfeel that oaking brings, many of our customers say is far superior than anything they have tried before


Stoak’s extracts are all in highly concentrated liquid form, this has major benefits for our clients as it means simple addition with no mixing, preparation, mess or fuss. The extract goes to work immediately as it engages with the product immediately on a molecular level allowing for rapid and predictable integration.

There are no risks of scalping normally associated with powders, no need for lengthly circulation associated with solids and no requirement for post-addition filtration, simply add, pump through and allow our extract to do its work.


All of our products are certified organic and registered as GRAS (Generally recognised as safe), they fall under the harmless colouring, flavoring and blending materials category and are suitable for use in a wide variety of food and beverage products.

Being organic registered means you have the piece of mind that our products are safe for use in your products whilst ensuring that we are compliant with any organic certification you have or are applying for.

Stoak products carry additional certifications including Non-Allergen, Non-GMO, Kosher, Heavy metal and pesticide free, Kosher, Halal and more.


The Stoak organisation is geared toward supporting ongoing knowledge, understanding and the expansion of our extraction technology and products.

From our technical team through to our sales and client support infrastructure we are constantly developing the application and extraction technology.

Our drive is to better understand how nature is acting in our product and how this can assist food and beverage clients in meeting both their current and future product development and stability challenges as well as saving on costs in essential production processes.


Our preservation products have all been extensively tested to ensure that they do not interfere in any way with your existing recipe or product profile.

The Stoak range of preservatives have been specifically formulated and extracted to make sure that we are only targeting the congeners, tannins and phenols specifically aimed to preserve, not flavor.

Dosing rates are extremely low and testing has been carried out on extremely sensitive food types with no identifiable change. We work closely with all of our clients to ensure that any concerns are managed at the trial phase.


Stoak regularly engages with its clients to assess and test the unique requirements of their product development teams. This involves product formulation, extract variant analysis as well as product application testing.

We have trail protocols, white papers and programs setup to undertake full evaluation and testing to provide proof of concept and stability analysis with our clients. In all cases we work hand in hand with the client developing the right mix of ingredients for use in their products.