Greaseproof vs Glassine vs PE-Lined Paper Bags: Which Stops Pastry Grease Without Sogginess?
Quick answer
For warm, buttery pastries such as croissants that are eaten the same day, a greaseproof paper bag (or a kraft bag with a greaseproof inner ply) is usually the best balance: it holds back butter stains while still letting steam escape so the crust stays crisp. Glassine looks cleaner and resists grease well, but it is stiffer, can crack at folds and is not a moisture barrier. A PE-lined bag gives the strongest grease and moisture barrier, but it traps steam, so warm pastries can turn soft; it suits cooled, very oily or longer-held items better. Confirm the choice by bagging your own product on a sample.
Quick facts: Bakery Paper Bags
- Indicative unit price: about US$0.10–0.30 per bag. This is a guide, not a quotation: the final price depends on size, material, print colours, finish and order quantity.
- MOQ: typically from 500 pcs per size and artwork; the confirmed minimum depends on material, print method and features and is stated on the quotation.
- Lead time: Physical samples 5–7 working days after artwork is confirmed; bulk production 20–30 days after sample approval.
- Who makes it: BestPackFactory’s own factory in Longhua District, Shenzhen, China. Free dieline and artwork proof within 24 hours. See real samples and videos.
- Specifications and quote: Bakery Paper Bags · Request a quote
The real trade-off: grease out, steam out
A bakery bag has two jobs that pull in opposite directions. It must stop fat from wicking through the paper and staining the print or the customer’s hands, and it must let water vapour leave so a crisp crust does not go soft. Any barrier strong enough to block all grease and moisture will also hold steam inside. That is why the “best” material depends on whether the product is warm or cooled, how much butter or oil it contains, and how long it stays in the bag.
Paper weight, size and handles are a separate decision, covered in our paper bag GSM and load guide. This article only deals with the grease barrier.
Comparison table
| Property | Greaseproof paper | Glassine | PE-lined (poly-coated) paper |
|---|---|---|---|
| How the barrier is made | Highly refined, dense pulp; sometimes an added grease-resistant treatment | Refined pulp that is supercalendered (pressed very smooth and dense) | A thin polyethylene layer laminated or extruded onto paper |
| Grease hold-out | Good to very good, depending on grade | Good to very good | Very high |
| Steam and breathability | Lets vapour escape reasonably well | Partly breathable | Low; traps moisture |
| Effect on warm, crisp pastry | Crust usually stays crisp | Usually acceptable for short holds | Crust can soften as condensation forms |
| Look and feel | Soft, matte, often white or natural brown | Smooth, glossy, translucent | Depends on the outer paper; inside feels plastic |
| Heat sealing | Generally not heat-sealable | Generally not heat-sealable unless coated | Heat-sealable PE side is common |
| Recycling questions | Typically treated as paper; check local rules | Typically treated as paper; check local rules | Paper-plastic combination; acceptance varies by local scheme |
| Typical bakery uses | Croissants, Danish, warm rolls, sandwiches | Cookies, small pastries, display or tea-shop bags | Fried or very oily items, cooled goods held longer, frozen pastries |
Performance varies by grade, basis weight and supplier. Confirm on a sample with your actual product and holding time.
Greaseproof paper
Greaseproof paper gets most of its resistance from very finely refined fibres packed tightly together, which leaves few open channels for fat to travel through. Grades differ a lot, and suppliers commonly describe grease resistance with a KIT rating from the TAPPI T 559 test, where a higher number means better hold-out. Butter-rich laminated pastries usually need a higher rating than bread or plain rolls. Greaseproof is also a common choice as the inner ply of a two-layer bag, with printed kraft on the outside for strength and branding.
Ask how the grease resistance is achieved. Some markets now restrict fluorinated (PFAS) grease treatments in food-contact paper, so many buyers specify a fluorochemical-free grade and request the matching declaration for their market.
Glassine
Glassine is pressed between polished rollers until it becomes smooth, dense and slightly see-through. That density gives it good grease and air resistance and a premium, clean look, which is why it is popular for cookies, macarons and small pastries sold in tea shops and patisseries. The weak points are stiffness and fold cracking: sharp creases can open tiny cracks that let grease through, and glassine is not a reliable moisture barrier. It can also become brittle in very dry conditions and lose stiffness in humid ones.
PE-lined paper
A polyethylene layer on the food side gives the strongest barrier to both fat and liquid, and the PE can be heat-sealed for a closed bag. That makes it useful for fried snacks, very oily pastries, frozen or chilled goods and products that sit in the bag for hours. The same barrier stops steam escaping, so a croissant bagged straight from the oven tends to soften as condensation forms on the inside. If you use PE-lined bags for warm items, consider letting products cool first, adding vent holes or using a window or open top. Recycling acceptance for paper-plastic combinations varies, so check the local scheme in your sales market. For coating alternatives, see PE vs PLA vs water-based coatings.
Decision rules
- Warm croissants and Danish, sold for same-day eating: greaseproof bag or kraft outer with greaseproof inner ply.
- Cookies, macarons, small dry pastries on display: glassine, often as a flat or window bag.
- Fried items, very oily fillings, or goods held for hours: PE-lined, ideally with venting for anything packed warm.
- Bread and plain rolls: plain kraft or a lighter greaseproof grade is often enough.
- Printed outside must stay clean: use a two-ply construction rather than relying on one sheet.
What to send in an RFQ
- The products going into the bag, whether they are packed warm or cooled, and how long they stay bagged.
- Preferred barrier (greaseproof, glassine or PE-lined) or a request for a recommendation.
- Any target grease rating to verify on samples, and whether a fluorochemical-free grade is required.
- Bag style (flat, satchel with gusset, window bag), size and paper colour.
- Print coverage and whether ink sits on the outer ply only.
- Destination market and any food-contact documents you need.
- Quantity per size; custom orders start from 500 PCS.
Common mistakes
- Choosing PE-lined bags for oven-warm croissants and then blaming the recipe for soft crusts.
- Approving a sample with a dry test item instead of the butteriest product on the menu.
- Testing for only a few minutes when real customers carry the bag for an hour.
- Creasing glassine sharply at folds, which can open micro-cracks.
- Assuming a recycling claim without checking the local scheme in the sales market.
Frequently asked questions
Which paper bag is best for croissants?
For warm croissants eaten the same day, a greaseproof bag or a kraft bag with a greaseproof inner ply is usually the best balance, because it resists butter stains while letting steam escape.
Is glassine greaseproof?
Glassine resists grease well because it is pressed very smooth and dense, but it is not a moisture barrier and can crack at sharp folds.
Why do pastries go soggy in PE-lined bags?
The polyethylene layer blocks steam, so moisture from warm pastry condenses inside the bag and softens the crust. Cooling products first or adding vents helps.
How is grease resistance measured?
Suppliers commonly quote a KIT rating from the TAPPI T 559 test, where a higher number means better grease hold-out. Confirm the result on a sample with your own product.
Related pages
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Send the products, whether they are packed warm, holding time, preferred barrier, bag style, size and quantity. Every BestPackFactory product is made in our own factory, and custom orders start from 500 PCS. Material, size and finish recommendations are confirmed in the quotation for your project. You can also reach Lisa on WhatsApp +86 158 8653 0985 or at lisa@colorprintingpackage.com.
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