Nitrogen Flushing and Coffee Cans: What Roasters Need to Know

XYH CAN · December 2026 · 4 min read

Specialty roasters are moving some of their range into cans. US coffee can shipments were up 40.6% in Q2 2026 (CMI), and the roasters we talk to give the same reason: shelf presence and a longer, more stable shelf life than a bag. Both of those depend on getting oxygen out of the package and keeping it out. That is what nitrogen flushing is for, and the can has a specific job in making it work.

We are a can factory, not a coffee packer, so this post sticks to what we know: what the can must do, and what to ask your filler.

What nitrogen flushing does

Roasted coffee loses aroma through oxidation. Nitrogen flushing replaces the air in the headspace with nitrogen, an inert gas, just before the package is sealed. Less oxygen means slower staling. Flushing is done on the filling line, not at the can factory. Our cans arrive empty and clean; your filler flushes and seals.

Freshly roasted coffee also releases carbon dioxide for a period after roasting. Bags handle this with a one-way valve. A rigid can does not have a valve, so roasters typically let whole bean rest before canning, or work with a filler who has set the process for cans. Ask your co-packer how they handle degassing for rigid containers; it is the first question that decides whether a can is right for your product.

What the can must do

For flushing to be worth anything, the can has to hold the nitrogen in and the oxygen out until the consumer opens it. That comes down to four things.

1. A sound body seam. Our bodies are welded on automatic resistance welding lines and the seam is coated inside. A leaking side seam defeats the flush. This is visible on the factory page.

2. The right primary seal. For a can that is opened once and stored, the peel-off membrane end is the common choice. It is heat-sealed onto a steel ring after the flush and gives a full barrier. For a can the consumer scoops from over weeks, a membrane end plus a PP overcap gives barrier until first open and reclose after. Some roasters prefer an easy-open end with a screw lid over it. Our lid guide explains the trade-offs.

3. A lining matched to coffee. Coffee is dry and oily. We select the internal coating for the product filled, and the coatings we use are tested to FDA 21 CFR 175.300 with the report available on request. BPA-NI lining is available. Details on compliance.

4. Correct seaming at your filler. The end diameter must match your filler's seamer, and the double seam must be set correctly. We supply the can dimensions and end specification for your filler to set up against.

Sizes roasters use

Heights are adjustable within the body range, so a 250g and a 340g can share a diameter and a lid. Full sizes are on can sizes and lids and the product range on coffee cans and tea tins.

Printing a coffee can

Coffee is a shelf product and the can is the label. We print the flat tinplate sheet on a Heidelberg CMYK offset press and a Mitsubishi 5-colour metal decorator before forming, with gloss or matte varnish. Matte varnish is popular with specialty roasters because it photographs well and hides fingerprints. Screw-cap coffee and tea tins start at 10,000 printed pieces; unprinted cans have no minimum, which is a reasonable way to test a canned SKU with a paper label before committing to print. See custom printing.

What to ask your filler before you order cans

• Do you flush rigid containers, and what residual oxygen do you target? (Their number, not ours.)
• Which end diameter is your seamer set for?
• How do you handle CO2 release from fresh roast in cans?
• Do you want cans delivered with the bottom end seamed and the top end loose? (This is standard.)

Bring their answers to us and the can specification follows from them.

Straight talk

If you sell most of your coffee within two weeks of roasting through a café or subscription, a valve bag is cheaper and does the job. Cans earn their cost when you need months of shelf life, retail presence, a gift format, or a premium line. We would rather you can the right SKU than the whole range.

Next step

Send us the fill weight, the closure you prefer and your filler's seamer specification, and we will quote and sample within about seven days. Go to /quote/.