We Prototyped "Chestnut Skin Powder" Using Domestically Grown Chestnut Skins

February 23, 2026April 22, 2026

Summary of this article

Agriture prototyped a "chestnut skin powder" made from domestically grown chestnut skins. We carefully wash and dry domestic chestnut skins and finish them into a fine powder—glucose-free and uncolored. Rich in polyphenols, tannins, and dietary fiber, it can be applied to a wide range of products such as baked goods, bread, smoothies, and tea.

Agriture prototyped a "chestnut skin powder" made from domestically grown chestnut skins.
Chestnut skins have long been a by-product often discarded during food processing, but they're drawing attention as a sustainable material. In particular, chestnut inner and outer skins are rich in polyphenols and tannins, and they're seen as promising functional materials with antioxidant activity.

For this prototype, we carefully washed and dried domestic chestnut skins and finished them into a fine powder. Made without additives, glucose-free and uncolored, it features the material's own toasty aroma and pale brown color. By drawing on the chestnut's own aroma and deep, rich taste, it can be applied to a wide range of products—baked goods, bread, smoothies, tea, and more.

Chestnut skin is also rich in dietary fiber, making it suitable for health-oriented product development. It has particularly high affinity with development themed around the currently trending "upcycled food" and "domestic functional materials," and OEM inquiries from food manufacturers, confectioners, and beverage companies are increasing.

Agriture handles everything from material sourcing through drying, powdering, and OEM manufacturing in-house. If your company is considering product-making that draws on domestic materials such as chestnuts, please feel free to inquire.

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About Agriture's vegetable powders

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Features of chestnut skin powder and component insights

Chestnut skin powder is made by drying and grinding the inner and outer skins that come out as by-products during chestnut processing. As an "upcycled food" that powders parts usually discarded, it's drawing attention in product development in the context of food-loss reduction and the SDGs. The inner skin contains polyphenols (tannins) and dietary fiber, and it features a distinctive flavor with a mild bitterness and astringency. Since content varies with the chestnut's variety and origin, we recommend confirming the flavor of the lot at the prototype stage. For detailed specs, seethe chestnut skin powder product page.

Difference from chestnut kernel powder

Chestnut skin powder differs from powder made from the chestnut kernel (edible part) in both application and flavor design. When comparing at the development stage, use the table below as a guide (figures vary with variety and processing conditions).

Item	Chestnut skin powder (inner and outer skins)	Chestnut kernel powder (edible part)
Key component insights	Polyphenols (tannins), dietary fiber	Starch, carbohydrate, vitamin C
Flavor	Mild bitterness, astringency, woody aroma	Sweetness, chestnut-like flavor
Main use	Baked goods, tea, bread, cereal bars	Mont Blanc, kurikinton, paste
Upcycling nature	Excellent (effective use of a discarded part)	Fair (uses the edible part as is)
Color	Brown to deep brown	Pale beige to yellow

The tannins in chestnut skin are perceived as astringency, so the blend ratio and balance with other materials are key to product design. Designs that combine it with materials compatible with bitterness and astringency—such as chocolate or coffee—are common.

You can check the details of turnip's powder form on the

Chestnut skin powder is an upcycled material that "turns a once-discarded part into a product." It has high affinity with product plans themed around the SDGs and food-loss reduction, and it's a material whose story is easy to convey on the package. Since the strength of astringency varies by lot, we recommend a sensory evaluation of the blend ratio at the prototype stage.

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Chestnut skin powder can be used in product design from both angles: the functionality of "polyphenols and dietary fiber" and the story of "upcycling." Here are representative ideas by application.

Baked goods, bakery

Chestnut skin powder's mild bitterness and woody aroma pair excellently with chocolate-based baked goods and bread. Kneading 2–5% into financier, galette, or brownie dough adds a deep, grown-up flavor. Combining it with candied inner-skin chestnuts or marron paste for "all-chestnut sweets" is also used in prototypes.

Kneading material for chocolate brownies and galettes
Grown-up flavor for financiers and madeleines
Flavoring for rye bread and whole-wheat bread

Tea, herbal tea

"Chestnut skin tea," made by roasting and grinding chestnut skin, is popular with health-conscious consumers as a caffeine-free tea. Blended with hojicha or rooibos, the astringency softens for an easier-to-drink design. It also has a prototype track record for filling into tea bags and as a material for bottled beverages.The nutritional value and benefits of vegetable powder.

Standalone and blend products of chestnut skin tea (caffeine-free)
Blending material for Japanese herbal teas
Blending material for bottled beverages and drink bases

Cereal, granola, energy bars

Chestnut skin powder, which contains dietary fiber, is a material we frequently receive inquiries about as a material for cereal bars and granola. Combined with nuts and dried fruit, you can put forward a dual concept of "upcycling × dietary fiber."Vegetable powder list pageAn ingredient for oden and pot-au-feu

Blending ingredient for granola and muesli
Dietary fiber ingredient for energy bars and protein bars
SDGs-concept cereal products

Health foods, supplements

There is also demand for it as a health-food ingredient, drawing on the polyphenols (tannins) and dietary fiber found in chestnut skins. The powder form works for tablets, granules, and capsules alike.

Polyphenol supplement ingredient
Health food ingredient with dietary fiber blended in
Wellness products using upcycled ingredients

A base raw material for vegetable bouillon and dashi powder

Here are the representative specifications for Agriture's commercial lots of chestnut-skin powder. From an upcycling standpoint that puts otherwise discarded parts to good use, we handle everything in-house, from raw-material sourcing through milling.Chestnut-skin powder specificationsplease refer to together with.

A vegetable base powder for baby food

Item	Agriture's manufacturing specs and OEM support
Raw materials	Inner and outer skins of Japanese-grown chestnuts (a by-product of chestnut processing)
Processing step	Washing → drying → roasting (as needed) → milling → filling
Additives	No colorants or antioxidants used
Storage period	A guide of about 6 months from the shipping date (varies by storage conditions)
Processing shape	From 1 kg of raw material
Main production lot	Slice / dice cut / powder
Not used	Minimum prototyping lot

Customization support

Roasting: choose from unroasted (raw-dried), light roast, or dark roast (a major factor in flavor design)
Packaging: four types—500 g bag, 1 kg bag, 5 kg commercial bag
Shape: slice (for pickles), dice cut (for ingredients), powder
Growing region: multiple domestic contract-cultivation routes prepared

Blending: pre-blend support with other dried vegetables

Because the flavor of chestnut-skin powder changes dramatically with the presence and depth of roasting, we recommend narrowing down your target flavor during the prototype stage.

dried vegetable / powder OEM inquiry formContact us with the prototyping content, application, and desired specifications via
Share your intended product and roasting direction in a concept interview (via Zoom or email)
We ship prototype samples in 1 kg units of raw material (typically 2–3 weeks). Comparative prototypes across roast levels are possible.
Contact us with the prototyping content, desired shape, and assumed application via
Main manufacturing (from 10 kg of raw material). Issuing necessary documents and lot-by-lot quality inspection supported

Tell us your application—such as “dark roast for baked goods,” “light roast for tea,” or “unroasted for supplement use”—and we’ll propose the optimal processing conditions.

Product catalog showing the items we handle

Flexible support from small lots to large lots

Sold in small lots from 100g
Handling heirloom vegetables from across Japan
Dried fruits and herbs also supported

Download here

Frequently asked questions

Q. How astringent is chestnut-skin powder?

A. It has a tannin-derived bitterness and astringency. A deeper roast tends to soften the astringency and bring the toasty notes forward. Since the perceived astringency can be adjusted through the blend ratio and paired ingredients (chocolate, nuts, hojicha, and the like), we recommend sensory evaluation at the prototype stage.

Q. Can we label it as an “upcycled food” on the package?

A. You can state that the product uses a chestnut-processing by-product as its raw material. However, since the legal standards around the term “upcycled” remain in flux, please make the final decision on package labeling together with your own legal and quality-control departments.

Q. Can it be blended with other vegetable powders?

A. Yes. We can design original blends combining it with the 60-plus vegetable, herb, and fruit powders Agriture processes.Vegetable powder list pagePlease check the items on

Q. Can you issue a certificate of raw material origin and an analysis table?

A. We can issue both a certificate of raw-material origin showing it is a domestic raw material and a microbial test report.

Q. Can it be blended with other dried vegetables?

Author of this article

Rei Kojima Agriture CEO

CEO of Agriture Inc. Runs a contract processing and OEM business centered on dried vegetables and dried fruit. In partnership with farmers within Kyoto Prefecture, he pursues “sustainable food distribution” through the use of non-standard vegetables and support for sixth-industrialization. Drawing on extensive hands-on experience at manufacturing sites, he provides support that walks alongside every business considering OEM—from product planning and prototyping to small-lot handling, packaging design, and sales-channel development.

We Prototyped "Chestnut Skin Powder" Using Domestically Grown Chestnut Skins