C40 MK4
A premium stainless-steel hand grinder with steel burrs, an oak knob, and a glass catch jar - one of the closest things to a plastic-free grinder, with one caveat (a BPA-free plastic internal frame in the grind path).
Plastic-free verdict: Minimal plastic contact
The body, crank, and axle are stainless steel, the burrs are Comandante's proprietary high-nitrogen martensitic stainless steel, and the knob is natural oak - the brand deliberately uses no aluminum. It ships with two jars: an amber glass bean/catch jar and a shatter-resistant clear polymer (BPA-free plastic) jar, so you can run the grounds path entirely in glass. The one unavoidable plastic is the "BPA-free plastic internal frame" inside the grinder that beans pass through on their way to the burrs; that keeps it from being a fully plastic-free grind path. Bearings use rubber seals, but those aren't in the food path.
Verification: Manufacturer confirmed · reviewed 2026-07-06
What it's made of
| Part | Material | Food contact |
|---|---|---|
| body stainless steel (some models with wood veneer); no aluminum used | Stainless Steel (304 / 18-8) | No |
| burrs proprietary "Nitro Blade" high-nitrogen martensitic stainless steel, ~58 HRC | Stainless Steel (304 / 18-8) | Yes |
| internal frame (grind path) BPA-free plastic internal frame beans pass through; the one plastic in the contact path | Plastic (other / unspecified) | Yes |
| bean jar amber glass jar; clear glass jars also available separately | Soda-Lime Glass | Yes |
| catch jar (alternate) shatter-resistant clear BPA-free polymer jar; optional - a glass jar is included and can be used instead | Plastic (other / unspecified) | Yes |
| knob 100% natural oak, hand-made | Wood | No |
| bearing seals rubber seals on the stainless micro ball bearings; not in the food path | EPDM Rubber | No |
Comandante's flagship hand grinder, hand-assembled in Germany's Black Forest. The stainless-steel body and high-nitrogen "Nitro Blade" steel burrs are widely considered a benchmark for grind quality in a manual grinder, and the brand's deliberate avoidance of aluminum plus its inclusion of a glass catch jar make it about as close to plastic-free as a high-end grinder gets. The honest caveat: MK4 units use a BPA-free plastic internal frame that beans pass through, so the grind path is not 100% metal/glass. If you use the glass jar, the only plastic your coffee touches is that internal frame.
Pros
- All-stainless body and burrs; no aluminum by design
- Ships with a glass catch jar, so the grounds path can be glass + steel
- Oak wood knob; premium build and excellent grind quality
- Steel burrs are extremely durable and rebuildable
Cons
- BPA-free plastic internal frame in the grind path - not a fully plastic-free path
- Expensive
- The second (polymer) jar is plastic; use the glass one to avoid it
Notes
- Ships with two ~40g jars: one amber glass, one clear BPA-free polymer; extra glass jars sold individually and in 4-packs
- Older MK3 glass jars, crank, and pommel are backwards-compatible with the MK4
Categories: Coffee Grinders
Sources
Every material claim above is backed by these. This is the scattered info we centralized.
- manufacturer https://comandantegrinder.com/pages/faq brand states no aluminum used; ships one glass and one polymer bean jar; 100% natural wood knob; extra glass jars available
- review https://prima-coffee.com/equipment/comandante/c40-mk4-coman-pp retailer spec sheet - stainless steel body, high-nitrogen martensitic steel burrs, oak knob, "BPA-free plastic internal frame", rubber-sealed steel bearings, amber glass and clear polymer jars
- review https://www.amazon.com/Comandante-4260113435663-Nitro-Blade-Black/dp/B07JQ4P976 listing confirms MK4 ships with one brown glass jar and one clear polymer (shatter-resistant) catch jar