Soft packaging (flow pack, doy pack, sachet): types and application
General logic: why three different types at all
Soft packaging solves one task — to protect the product with minimal material. But products behave differently: granular coffee does not leak, liquid sauce spreads, and a 5 ml portion of shampoo does not even need a separate rigid form. Hence, three constructions with different complexity of seams, different film consumption, and different price per unit.
Flow pack — the simplest form, three seams, minimum film waste, but the packaging does not stand on the shelf by itself. Doy pack — five seams and a pleat-gusset at the bottom, which allows the package to open and maintain vertical position. Sachet — a miniature version of the same logic, designed for volumes from 1 to 100 ml or grams and requiring large runs — from 100 to 600 thousand units, depending on the size of the packet.
What to choose for granular, liquid and unit products
There is no universal answer, but there is a clear link to the product's physics and how it will be sold.
| Product type | Recommended packaging | Why |
|---|---|---|
| Granular (grains, coffee, spices) | Doy pack with zip-lock or flow pack | A secondary seal is required after opening; a doypak is convenient for shelf storage, while a flowpak is suitable for large runs without premium positioning |
| Liquids (sauces, baby food, beverages) | Doypak with a spout | The spout provides controlled dispensing and dosing, which a flowpak cannot provide |
| Unit and portioned (sugar, salt, cosmetic samples) | Sachets | Small volume makes rigid packaging economically meaningless, while a flowpak is excessive in area |
| Frozen and vacuum-packed products (meat, fish) | Flowpak or doypak made from polyamide/aluminum foil materials | Need strength against rupture during freezing and low oxygen permeability |
Economics: where doypak pays off, and where flowpak is more advantageous
Flow-pack is almost always cheaper on a per-unit basis: three seams instead of five, less film for packaging, higher packaging speed on the line. At print runs of over several hundred thousand units per month and low product margin — this is a practically irreplaceable option. That is exactly why large grocery brands in mass market more often use flow-pack for basic positions.
Doy-pack pays off where packaging itself participates in sales. The vertical position on the shelf increases the visibility of the front label — faceing — almost twofold compared to a horizontally lying flow-pack. For a store this means more effective use of shelf meter: the same area can hold more units of product with the front facing the customer. For a brand — higher perceived value and ability to maintain a price 10–20% higher than competitors at comparable product cost.
Sache is a separate economy: print run determines everything. A minimum order of 100 thousand units makes sache unprofitable for a test launch, but when entering retail networks with samples or portion formats, this is the only viable option from a per-unit cost standpoint.
Barrier properties of the film: not a decorative layer, but the product's shelf life
The thickness of the doy-pack film usually stays within the range of 80–160 micrometers, and this is not a random spread — directly affects puncture resistance and form rigidity. But thickness does not solve everything: the key role is played by the layer structure.
- Two-layer film (PE + lavsan/polypropylene) — standard for dry and not very aggressive products: the inner polyethylene provides seam tightness, the outer layer is responsible for printing and rigidity.
- High-barrier EVOH or foil layers — reduce oxygen permeability to less than 1 cm³/m²/day. Without this, coffee and tea oxidize and lose their aroma within weeks instead of months.
- Polyamide and foil structures — are used for vacuum packaging of meat, where both mechanical strength and tightness during air evacuation are important.
- Retort film — a specialized multi-layer material that withstands sterilization in an autoclave at a temperature above 100°C. This allows a product that in regular packaging lasts 10 days (like milk) to remain unrefrigerated for up to 2 years.
The mistake that is often made at the start of production is to choose film based on price per meter, rather than oxygen permeability. For fatty and aromatic products, this is a direct path to complaints about 'going bad within a month'.
Additional functions: when they are justified, and when they are unnecessary expenses
Zip-lock, a spout, and a transparent window increase packaging cost by 5–15%, and should only be included where the consumer actually benefits.
- Zip-lock Needed for products that are repeatedly opened and closed: cereals, snacks, pet food. Repeated use directly influences the perception of the brand as customer-oriented — this is not aesthetics, but a measurable factor affecting repeat purchases.
- Spout Justified only for liquid and viscous products requiring measured dispensing: infant formula, cosmetics, sauces. For dry products, a spout is meaningless and simply increases production costs.
- Transparent window Works where the appearance of the product is part of the selling message: nuts, dried fruits, baked goods. For powders and liquids, the window does not provide an effect and becomes a decorative element without function.
Why the doy-pack appeared exactly in 1963 year
The doy-pack, technically called a Stand Up Pouch (SUP), was invented by Frenchman Louis Duainen at the company Thimonnier. The first application was packaging fruit juice and olives, that is, products that were previously packed either in rigid containers or in packaging that could not stand on a shelf. The 1960-s marked the period of mass expansion of supermarkets to a new level of retail organization: self-service required packaging that could sell itself, without a clerk behind the counter.
The construction with a gusset at the bottom solved this exact problem: the package folds flat for transportation but unfolds and gains volume when filled with liquid or granular product, acquiring stability. This simultaneously reduced logistics costs—flat blanks occupy several times less space during transport than finished packaging—and solved the shelf visibility issue. Since then, the five-seam construction has changed very little in its basic geometry, with only the materials and additional functions being modified.
The psychological effect of vertical positioning for the consumer is also real and measurable: packaging standing 'like a can' is subconsciously perceived as more premium and reliable compared to a lying bag, even if the contents are identical. This is one of the reasons why the doypack has become established in categories with high competition for attention — children's nutrition, coffee, premium snacks.
General logic: why three different types at all
Soft packaging solves one task — to protect the product with minimal material. But products behave differently: granular coffee does not leak, liquid sauce spreads, and a 5 ml portion of shampoo does not even need a separate rigid form. Hence, three constructions with different complexity of seams, different film consumption, and different price per unit.
Flow pack — the simplest form, three seams, minimum film waste, but the packaging does not stand on the shelf by itself. Doy pack — five seams and a pleat-gusset at the bottom, which allows the package to open and maintain vertical position. Sachet — a miniature version of the same logic, designed for volumes from 1 to 100 ml or grams and requiring large runs — from 100 to 600 thousand units, depending on the size of the packet.
What to choose for granular, liquid and unit products
There is no universal answer, but there is a clear link to the product's physics and how it will be sold.
| Product type | Recommended packaging | Why |
|---|---|---|
| Granular (grains, coffee, spices) | Doy pack with zip-lock or flow pack | A secondary seal is required after opening; a doypak is convenient for shelf storage, while a flowpak is suitable for large runs without premium positioning |
| Liquids (sauces, baby food, beverages) | Doypak with a spout | The spout provides controlled dispensing and dosing, which a flowpak cannot provide |
| Unit and portioned (sugar, salt, cosmetic samples) | Sachets | Small volume makes rigid packaging economically meaningless, while a flowpak is excessive in area |
| Frozen and vacuum-packed products (meat, fish) | Flowpak or doypak made from polyamide/aluminum foil materials | Need strength against rupture during freezing and low oxygen permeability |
Economics: where doypak pays off, and where flowpak is more advantageous
Flow-pack is almost always cheaper on a per-unit basis: three seams instead of five, less film for packaging, higher packaging speed on the line. At print runs of over several hundred thousand units per month and low product margin — this is a practically irreplaceable option. That is exactly why large grocery brands in mass market more often use flow-pack for basic positions.
Doy-pack pays off where packaging itself participates in sales. The vertical position on the shelf increases the visibility of the front label — faceing — almost twofold compared to a horizontally lying flow-pack. For a store this means more effective use of shelf meter: the same area can hold more units of product with the front facing the customer. For a brand — higher perceived value and ability to maintain a price 10–20% higher than competitors at comparable product cost.
Sache is a separate economy: print run determines everything. A minimum order of 100 thousand units makes sache unprofitable for a test launch, but when entering retail networks with samples or portion formats, this is the only viable option from a per-unit cost standpoint.
Barrier properties of the film: not a decorative layer, but the product's shelf life
The thickness of the doy-pack film usually stays within the range of 80–160 micrometers, and this is not a random spread — directly affects puncture resistance and form rigidity. But thickness does not solve everything: the key role is played by the layer structure.
- Two-layer film (PE + lavsan/polypropylene) — standard for dry and not very aggressive products: the inner polyethylene provides seam tightness, the outer layer is responsible for printing and rigidity.
- High-barrier EVOH or foil layers — reduce oxygen permeability to less than 1 cm³/m²/day. Without this, coffee and tea oxidize and lose their aroma within weeks instead of months.
- Polyamide and foil structures — are used for vacuum packaging of meat, where both mechanical strength and tightness during air evacuation are important.
- Retort film — a specialized multi-layer material that withstands sterilization in an autoclave at a temperature above 100°C. This allows a product that in regular packaging lasts 10 days (like milk) to remain unrefrigerated for up to 2 years.
The mistake that is often made at the start of production is to choose film based on price per meter, rather than oxygen permeability. For fatty and aromatic products, this is a direct path to complaints about 'going bad within a month'.
Additional functions: when they are justified, and when they are unnecessary expenses
Zip-lock, a spout, and a transparent window increase packaging cost by 5–15%, and should only be included where the consumer actually benefits.
- Zip-lock Needed for products that are repeatedly opened and closed: cereals, snacks, pet food. Repeated use directly influences the perception of the brand as customer-oriented — this is not aesthetics, but a measurable factor affecting repeat purchases.
- Spout Justified only for liquid and viscous products requiring measured dispensing: infant formula, cosmetics, sauces. For dry products, a spout is meaningless and simply increases production costs.
- Transparent window Works where the appearance of the product is part of the selling message: nuts, dried fruits, baked goods. For powders and liquids, the window does not provide an effect and becomes a decorative element without function.
Why the doy-pack appeared exactly in 1963 year
The doy-pack, technically called a Stand Up Pouch (SUP), was invented by Frenchman Louis Duainen at the company Thimonnier. The first application was packaging fruit juice and olives, that is, products that were previously packed either in rigid containers or in packaging that could not stand on a shelf. The 1960-s marked the period of mass expansion of supermarkets to a new level of retail organization: self-service required packaging that could sell itself, without a clerk behind the counter.
The construction with a gusset at the bottom solved this exact problem: the package folds flat for transportation but unfolds and gains volume when filled with liquid or granular product, acquiring stability. This simultaneously reduced logistics costs—flat blanks occupy several times less space during transport than finished packaging—and solved the shelf visibility issue. Since then, the five-seam construction has changed very little in its basic geometry, with only the materials and additional functions being modified.
The psychological effect of vertical positioning for the consumer is also real and measurable: packaging standing 'like a can' is subconsciously perceived as more premium and reliable compared to a lying bag, even if the contents are identical. This is one of the reasons why the doypack has become established in categories with high competition for attention — children's nutrition, coffee, premium snacks.
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