Two pallets of 8oz cups came back in February. Not defective — the buyer had pushed service to 92°C and held the cup under the steamer eleven seconds instead of five. Single wall is a product with a narrow tolerance, and most returns we see start with a menu change, not a factory fault.
We convert cups in Qingdao beside our bagasse lines, 2,500–3,000 tonnes of fibre and paper goods a year. Single wall is our busiest line: about 6 million units annually across 4, 6, 8, 12 and 16oz, on six forming machines, two shifts.
What “single wall” means on a drawing
One sheet formed into a cone, sealed on the side seam, bottom disc rolled in, rim curled on top. No second wrap, no air gap.
The board does everything: stiffness, insulation, barrier. Standard is 210–280gsm food-grade stock with PE or water-based coating inside. PE seals tighter on the side seam; water-based prints more cleanly outside but needs a warmer sealing plate. Buyers chasing the cheapest quote land on 210gsm PE, which is where the complaints start — a 210gsm 12oz cup feels flimsy within 90 seconds.
Rim diameter gets locked first. Our family is 90mm for 8–16oz, 80mm for 4–6oz, 62mm at 4oz. A 90mm lid will not sit on an 89mm rim, and both exist.
The spec table we quote from
| Size | Working volume | Rim (mm) | Base (mm) | Height (mm) | Board (gsm) | MOQ (pcs) | FOB Qingdao (USD/pc) |
|---|---|---|---|---|---|---|---|
| 4oz | 110–120ml | 62 | 45 | 58–62 | 190–230 | 50,000 | 0.021–0.030 |
| 6oz | 170–180ml | 80 | 50 | 72–78 | 210–250 | 50,000 | 0.026–0.036 |
| 8oz | 240–250ml | 80 / 90 | 50 / 52 | 90–95 | 230–280 | 50,000 | 0.032–0.045 |
| 12oz | 350–360ml | 90 | 55–58 | 110–115 | 250–300 | 30,000 | 0.042–0.058 |
| 16oz | 470–490ml | 90 | 58–60 | 130–136 | 280–320 | 30,000 | 0.052–0.072 |
These are plain stock with one-colour side print, ex-works Qingdao, inner poly bagging included, carton print not. Pulp prices shift monthly, and full-wrap CMYK adds roughly 8–15%. A first mixed container can go to 20,000 pieces per size inside four colours.
12oz is where the arguments start
A 12oz cup is nominally 355ml. Our brim figure runs 350–360ml, with the practical fill line 8–10mm below the rim. We print a fill line inside for café chains: the gap between 340ml and 360ml is the gap between “large” and a complaint.
Base diameter is the sneaky one. Two 12oz cups, 90mm rim, 110mm tall, hold volumes 20ml apart if one base is 55mm and the other 58mm. Both numbers belong on the PO.
Hot drinks: what single wall takes
PE-lined single wall is rated to 95°C contact. A 12oz 250gsm cup filled at 95°C hits 65–70°C on the outside within a minute, so espresso, tea and pour-over need a sleeve. The cup does not fail; the hand does.
From our line: a 90°C hold for five minutes shows no wicking at 250gsm, light bottom-seam softening at 210gsm. Past ten minutes the seam relaxes on thin grades and the cup cones.
If your product is soup, congee, hot chocolate held in a delivery bag, or a 20-minute tea, single wall is the wrong call at any grammage. If it is a 4–6oz espresso, a 90-second cold brew or soft serve, single wall is exactly right and you are not paying for a second wrap you do not need. Sleeves cost 0.008–0.015 USD each in kraft, and that is usually the honest add-on. Our 7oz single wall paper cups run is that use case at the small end.
Price reality: per piece is not per millilitre
4oz runs about 0.021–0.030 USD per piece; 16oz, 0.052–0.072. Per millilitre the 16oz is cheaper, but it eats more board, carton space and freight. What matters is per-serving margin.
A 12oz double wall cup runs roughly 35–50% more per piece — second board, extra wrapping station. You are buying insulation, not strength.
Freight is the forgotten line. A 40HQ holds about 1.1–1.4 million nested 8oz cups, 800–900 cartons at 1,000 pieces. Single wall nests 15–20% tighter than double, often cancelling a chunk of the unit price gap. A 40HQ to the US West Coast ran USD 4,500–8,500 through 2024–25; Rotterdam closer to 2,800–5,500. Paperwork sits outside all of it: FDA 21 CFR 176.170 for the US food-contact side, PPWR declarations for EU buyers from 2026 — check that locally.
Where our line ships, and where it breaks
Our biggest volume goes to coffee roasters in Australia and Canada on 80mm 6oz and 8oz, and soft-serve chains in the Gulf on 90mm 12oz. Failures cluster in three patterns:
- 250gsm water-based to 230gsm PE becomes “sweats at the seam” after six weeks in a humid warehouse. We shrink-wrap cartons for the tropics; 85% RH softens seam glue before the box opens.
- 90mm rim, 89mm lid, or a dome tooled for another wall thickness. Clicks on in Qingdao, pops off at the counter.
- Fine on heavy board, walks on thin stock. Proof on the grammage you buy.
Delivery-first operations should skip it. A sleeve adds a cent or two per unit and complicates packing; double wall is the boring answer.
What we need to quote
Rim diameter, working volume, board weight, lid yes-or-no. Four numbers, most of the back-and-forth gone. No rim figure? Send the lid you stock.
Sampling takes 7–10 days from artwork approval, three rounds per SKU. 500,000 units of one size runs 18–25 days in normal season, longer in August and December. OEM, plain stock, mixed containers all normal; FOB Qingdao by default, CIF on request.
For a stamped quote with your rim and volume, use the request quote form and attach the lid spec. Still weighing paper against fibre for hot service? Our bagasse soup containers with lids page covers the microwave question most cups get wrong. What a spec sheet cannot settle goes to the contact desk — we will say when single wall is the wrong buy.
FAQ
Are single wall paper cups microwave safe?
No, not the standard line. PE softens and the seam can open after 60–90 seconds. A water-based version handles 45 seconds, quoted per SKU.
Can single wall paper cups be used for cold drinks?
Yes, and well. Condensation makes the outside slick around the 90g of ice loaded into a 16oz. Sleeve or kraft finish for grip.
What is the difference between 8oz cups with 80mm and 90mm rims?
Diameter, not volume — both hold 240–250ml. The 90mm rim shares lids with a 12oz, so a café stocks one lid across two cups. 80mm needs its own.
What MOQ do you accept for a custom-printed single wall cup?
30,000 for 12oz and 16oz, 50,000 for 4–8oz, four colours or fewer. Mixed containers can go to 20,000 per size. Below that: plain stock with a label.
How hot can single wall cups go before failing?
PE grade handles 95°C. What fails first is the hand, about 65–70°C surface with 250ml. The cup softens after ten minutes of standing hot liquid on 210gsm; order 250gsm or heavier for long holds.
Do you supply matching lids?
Yes — flat PS/PP for cold, dome and sip for hot, 90mm and 80mm. Separate line item, approved on the real sample.
