# Glass jar or retort pouch for pickles and sauces: how much carbon does the switch change per unit shipped?

Canonical: https://senseible.earth/answers/glass-jar-vs-pouch-food-export-carbon

Switching from a glass jar to a retort pouch usually cuts packaging carbon per unit by most of the jar's footprint, because a pouch weighs a few grams against a jar's few hundred. Work it out as pack mass x material factor, plus the pack's own share of road and sea freight, for each option.

## What to include for each pack

- Primary pack: jar and lid, or pouch, by weighed mass per unit.
- Secondary pack: cartons and dividers. Glass often needs heavier cartons and partitions, so weigh those too.
- Freight of the pack itself: pack mass x tonne-km x factor for each leg, factory to port, sea, port to buyer. The food weighs the same in both, so it cancels out.
- Process differences: retort steam per batch if it differs between the two packs. Measure it rather than assume.
- Losses: breakage in glass and pouch leaks both waste product, which carries its own footprint.

## Why glass mass dominates

A jar for a 500 g pickle weighs far more than the pouch for the same fill. Even though a multilayer laminate has a higher footprint per kg than glass, its mass per unit is so much smaller that the jar almost always comes out higher. Sea freight per tonne-km is low, so freight usually adds less than the material itself; on air freight, the gap widens sharply.

## What the pouch costs you elsewhere

Glass is widely recycled and can be refilled; most retort laminates of PET, aluminium foil and polypropylene are not recyclable in practice. If your buyer asks for end-of-life emissions or recyclability, report them alongside the cradle-to-gate result rather than hide the trade-off.

## Making a public claim

If you plan to tell customers that the pouch has a lower footprint, ISO 14044 treats that as a comparative assertion. Both packs need the same functional unit, such as 500 g of product delivered to the buyer's warehouse, the same boundary and data quality, and a public comparison needs an independent critical review panel.

## Worked example: 500 g of pickle, India to a European port (factors assumed)

- Glass: jar 250 g at an assumed 1.0 kg CO2e per kg = 0.25 kg; steel lug cap 20 g at an assumed 2.0 = 0.04 kg; pack total 0.29 kg CO2e
- Glass freight: 0.00027 t x 500 km road x 0.0902 = 0.012 kg; 0.00027 t x 11,000 km sea x an assumed 0.01 = 0.030 kg
- Glass total: 0.29 + 0.012 + 0.030 = 0.33 kg CO2e per unit
- Pouch: 12 g at an assumed 8.0 kg CO2e per kg = 0.096 kg; freight 0.0005 + 0.0013 = 0.002 kg; total 0.098 kg CO2e
- Saving: 0.33 minus 0.098 = about 0.23 kg CO2e per unit
- On a 20,000 unit container: 20,000 x 0.234 = about 4,680 kg CO2e

The road factor is the Smart Freight Centre India default for a 12 to 20 t truck; the material and sea factors and the sea distance are placeholders. Use your supplier footprints and your forwarder's lane factor.

## What Senseible does here

Senseible reads the packaging purchase invoices and freight bills you would use for the weights and distances, and keeps them as evidence for the comparison.

- [Packaging footprint on export shipments](https://senseible.earth/answers/packaging-carbon-footprint-export-shipment)
- [Packaging end of life for food exporters](https://senseible.earth/answers/packaging-end-of-life-emissions-food-exporters)
- [Product carbon footprint calculator](https://senseible.earth/calculators/product-carbon-footprint)

Sources: [ISO 14044:2006, Life cycle assessment, requirements and guidelines (comparative assertions) (iso.org)](https://www.iso.org), [Smart Freight Centre, India Default GHG Emission Values V1.0 (May 2025), road table; GLEC Framework v3.0](https://www.smartfreightcentre.org), [GHG Protocol Product Life Cycle Accounting and Reporting Standard](https://ghgprotocol.org/standards)

Last reviewed 2026-10-19.