Cork Stopper Manufacturing: Where ABB Robots Fit

A natural wine cork is a cylinder punched from the bark of a cork oak, and making one still starts with a person and an axe. Cork stopper manufacturing has changed most after the harvest: cutting moved from hand carving to punching machines, and checking moved from the eye to X-rays, artificial intelligence and gas chromatography. This post follows the trade from a one-room cork shop in 1860s Pittsburgh to Corticeira Amorim's plants in northern Portugal, looks at the robots that pack stoppers today, and asks where ABB robots, which already pick and palletize small packs in food plants, could fit.

Used natural wine corks piled in a basket. Photo: Elisha Terada / Wikimedia Commons (CC0)

How cork stoppers were cut and checked by hand

Portugal produces about half of the world's cork, harvested between May and August by skilled strippers who cut and lift the bark without felling the tree. A cork oak can first be stripped at about 25 years old, and the bark then needs nine years to grow back, so Amorim says cork good enough for natural stoppers only comes from the third stripping, roughly 43 years after planting. A number painted on the trunk records the year of the last harvest. One tree can give 15 to 17 harvests over a life of 170 to 200 years.

Cork oaks with stripped, reddish trunks after the bark harvest. Photo: ralmonline alm / Wikimedia Commons (CC BY 2.0)

The Armstrong Cork Company shows how manual the trade once was. In 1860 Thomas M. Armstrong and John D. Glass opened a one-room shop in Pittsburgh, Pennsylvania, carving bottle stoppers from cork by hand, and made their first deliveries in a wheelbarrow. Armstrong branded each cork it shipped from 1864, and by the 1890s the company was the world's largest cork supplier. A booklet the company printed in 1909 shows long rows of workers "blocking" cork, paring large sheets of bark down before they were shaped into stoppers and other goods.

Workers blocking cork, paring down sheets of bark before shaping, at the Armstrong Cork Company in the Pittsburgh area, from its 1909 booklet. Photo: Armstrong Cork Company via Wikimedia Commons (public domain)

Today stoppers are punched from strips of boiled bark "either manually or automatically", Amorim says, and old cork-working machines are kept at the Cork Museum in Palafrugell, Catalonia. For winemakers the bigger worry was TCA, the main documented cause of cork taint. Amorim spent 12 million euros and six years developing NDtech, which tests every natural stopper individually by gas chromatography in a few seconds and removes any that release more than 0.5 nanograms of TCA per litre. A 2018 Forbes report cited by Equal Times said the system created more than 700 jobs.

An old cork-working machine on display at the Cork Museum in Palafrugell, Catalonia. Photo: Davidpar / Wikimedia Commons (CC BY-SA 3.0)

Inside Amorim's cork stopper plants today

Amorim, founded as a family business in 1870, now has about 4,000 employees, sells in more than 100 countries and makes over 1 billion euros a year, Euronews reported in September. It has put more than 90 million euros into research over ten years, and its P50 cork composite shields rocket launcher stages from heat. Stoppers remain its core business, and a harder one this year: in the first half of 2026 Amorim Cork's sales fell 7.2% to 366.8 million euros, partly because of a weaker mix in still wine stoppers. In October it launched ALØ, a range of stoppers for no and low alcohol drinks that keeps the pop of a pulled cork.

António Amorim, chief executive of Corticeira Amorim, speaking at the Horasis Global Meeting in Cascais, Portugal, in May 2017. Photo: Richter Frank-Jurgen / Wikimedia Commons (CC BY-SA 2.0)

In Amorim's plants the bark rests outdoors for at least six months, then boils for an hour in stainless steel tanks, which makes the planks swell by about 20%. Graded planks are cut into strips, stoppers are punched and polished, and each one is then checked by machine. A vision system using artificial intelligence classifies it by appearance, and rejects are ground into granules for technical stoppers. X-rays look for internal defects, clay and density changes, and NDtech screens for TCA. The stoppers are branded by heat, ink or laser, coated with paraffin or silicone and sealed in bags. Equal Times put Portugal's output at about 40 million stoppers a day in 2020.

Natural cork stoppers branded with producers' names, the kind of marking added by heat, ink or laser before coating. Photo: Hudson C. S. de Souza / Wikimedia Commons (CC BY-SA 4.0)

Robots have reached Amorim at the packing stage. The company used to ship stoppers in raffia sacks stacked on pallets. The Portuguese firm ESI Robotics built it a patented, fully autonomous packing cell, with an articulated robot stacking food-grade lined boxes on a pallet sized for shipping containers, that arranges the stoppers so 30% more fit in each load, Forbes Portugal reported in 2023. We found no ABB robot in a cork plant, but ABB robots do the same kind of job elsewhere. At Dot's Pretzels in Kansas, IRB 360 FlexPicker delta robots pick packs off a conveyor with vacuum grippers and an IRB 660 with a 3.15 m reach stacks the cases, so an ABB cell for stoppers is a possibility.

ABB IRB 360 FlexPicker delta robots picking packs off a conveyor on a packing line at Dot's Pretzels. Photo: ABB

Where cork stopper making goes next

Natural cork closes about 80% of the 20 billion bottles of wine made each year, so most bottles opened at home still have one, and Amorim says NDtech removes the risk of a TCA-tainted natural cork reaching drinkers. In October Amorim also detailed research on tirage corks, which seal sparkling wine during its second fermentation in place of crown caps. Its research director Miguel Cabral said wines aged under cork showed "less bitterness, more fruitiness" and more balance. Our post on wine bottling lines follows the stopper into the bottle.

A cork feeder pressing a natural cork into a bottle on a winery bottling line. Photo: Agne27 / Wikimedia Commons (CC BY-SA 3.0)

ESI's two newer packing lines for Amorim collect production data in real time, which helps manage output and predict maintenance needs. A robot cell for stoppers would most likely be simulated before it is built: for the Dot's lines, the integrator used RobotStudio with ABB's PickMaster add-in for the picking robots and Palletizing PowerPac for the palletizer. Picking items off a moving belt relies on conveyor tracking, which a FlexPicker would also need to lift stoppers from a sorting line.

An ABB IRB 660 palletizing robot stacking cases at Dot's Pretzels. Photo: ABB

The forest is the slowest part of the chain. A cork oak gives stopper-grade cork only after about 43 years, small and medium producers supply 90% of Amorim's cork, and its Rio Frio estate is testing ways to bring the first harvest forward. Sales are under pressure, and Amorim's group cut its average headcount in the first half. Harvesting is still done by hand, by strippers who pass their skills from generation to generation and, in 2020, earned 80 to 120 euros a day in a short season. Equal Times put direct employment in Portugal's cork industry at 12,000 to 14,000 people that year.

ABB FlexPicker robots placing snack bags into cases on the same packing line. Photo: ABB

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