From Fibre to Finished Product

The Milling
Process

Every bag we produce passes through the same sequence of steps it did in 1922 — refined, not replaced, by a century of accumulated knowledge.

Six Stages of Craft

01

Fibre Sourcing

We source 100% post-consumer recycled paper fibre — primarily from collected corrugated and mixed paper streams. Our procurement team audits each supplier annually for chain-of-custody certification, ensuring every batch meets our quality threshold before it enters the mill.

Paper rolls ready for processing
02

Pulping & Cleaning

Incoming fibre is hydrapulped — broken down in water to form a slurry — then passed through a multi-stage cleaning system to remove contaminants. Our original 1922 Hollander beater still operates alongside modern pressurised screens, combining heritage method with contemporary efficiency.

Lower Mills interior showing original machinery, c.1940
03

Sheet Forming

The cleaned pulp — at approximately 0.5% consistency — is distributed evenly across our Fourdrinier wire. Water drains through gravity and vacuum, forming a continuous web of paper. Basis weight is controlled to tolerances of ±2gsm, whether we are producing 70gsm tissue or 170gsm premium board.

Paper rolling machinery on the mill floor, c.1930s
04

Drying & Calendering

The wet web passes over a series of steam-heated drying cylinders, reducing moisture content from 80% to around 6%. A soft-nip calender then presses the sheet to the required smoothness and caliper — a critical step for print receptivity and fold-crack resistance in the finished bag.

Close-up of finished kraft paper surface
05

Printing & Finishing

In-house flexographic printing in up to six colours, with Pantone-matched inks and optional water-based varnish. For luxury clients, we offer foil-blocking and embossing via our registered converting partners. Proofs are supplied digitally and as physical press proofs before full-run approval.

Mill workers at finishing benches, c.1940s
06

Bag Making & Dispatch

Printed reels are slit and fed to our automatic bag-making lines. Handles — twisted paper rope, flat die-cut, or ribbon — are attached and glued under tension. Each production run is sampled every 200 units for handle-pull strength and base-seal integrity before palletising for dispatch.

Finished bespoke kraft paper carrier bags

Quality Assurance

Built to Last,
Made to Perform

Every production run at Stonehouse is supported by in-line quality checks and a dedicated QA team operating to ISO 9001:2015. Our bags are tested for handle tensile strength, base-seal integrity, and paper burst resistance before leaving the mill.

ISO

9001:2015 Certified

±2

gsm tolerance

6

colour flexo print

See It For Yourself

Mill visits are available for qualifying clients. Request a tour alongside your sample pack inquiry.

Request a Mill Visit