“It’s very upsetting when people come and try to kill you. We’ve had two funerals already. But when you have 70% of wines under cork, I think you can see that after fifteen years the debate has been resolved,” Carlos de Jesus started our meeting at Amorim.

I had taken advantage of my trip to Douro and the Dão to visit Amorim’s plant just to the south of Porto. Half of the world’s corks come from Portugal, Amorim has more than a third of the market, and roughly two thirds of business is in wine stoppers. There’s a plant farther south, near the forests, when the first processing is done, and then the sheets of cork are sent to the plant in the north to be turned into corks.

Sheets of corks come from the south

We visited the plant where both agglomerated corks (made of small particles) and solid corks (punched out from the sheet) are made. It’s actually technically easier to remove TCA from agglomerated corks, because the broken up particles can be heated to extract it before they’re stuck together into the cork. There’s a whole hall with a vast series of machines taking in raw cork and spewing out finished corks.

Raw cork goes in one end and agglomerated corks, free of TCA, come out the other end

To make solid cork, the sheets are cut into bars of the right width, and then the corks are punched out. There are two separate parts of the plant devoted to this, one automated, one manual. Watching the operators of the manual line seems like a time warp. They hold the bar in a machine, operate a treadle to punch out the cork, and then move the bar along to punch out the next cork. This seemed old fashioned compared with the automated equipment, but Carlos explained that the operator gets better results, just like manual grape harvest is better than mechanized!

Corks being punched out of bars on a automated line

After visiting the plant, we walked over to Amorim’s research facility, in a small building close by. The R&D department was created in 2000. A main objective is to find solutions to the TCA problem, but they’ve also been investigating the route for oxygen to enter bottles.

I was quite surprised when researcher Paulo Lopez explained that the routes for ingress are different for different closures. For synthetics and screwcaps, it’s permability from the exterior, but for cork it is the oxygen contained within all those little cellules in the cork itself. (Presumably this applies unless and until the cork loosens, but experiments show that this doesn’t happen in the first few years.)

Paulo says that the TCA problem is being significantly reduced. In 2003 the average TCA was 2.68 ng/l, now it is 0.62 ng/l. “We consider 0.5 ng/l to be zero as that is the limit of detection by available equipment. 1 ng/l is the sensitivity of the most sensitive human tasters.”

The lab does Q & A, testing 800 samples per day for TCA. This requires 24 hours to soak the cork and then 24 hours to get results. So it’s a check, but they have to wait 48 hours to release each batch.

Serried ranks of gas chromatographs in the lab

The latest system is NDtech, which analyzes individual corks. (If not secret, it’s certainly more closely guarded as no photos were allowed here.) Eight years in development, NDtech basically takes the gas chromatography system to automated speeds. A single production line can handle about 15,000 corks per day, and it costs 15¢ per cork.

Each line spews corks out into one of three bins: guaranteed below detection; at the edge of detection; and not acceptable. It didn’t look casually as though the second bin was that much less full than the first (the third was much smaller), but Paolo says the proportions are 65%, 30%, and 5%. “There are still too many false positives,” he says, “the next stage is to reduce them.”

It was a major feat to automate the equipment to this point, but capacity is still limited. There will be about 15 million NDtech corks this year and 60 million next year, which is probably way below demand. “Looking at individual corks is the holy grail. NDtech analyzes individual corks, but I doubt that we’re going to apply it to billions of corks. We’ll start with 50 million corks and then we’ll scale up. We’re not here to defeat TCA and go out of business. We need to defeat TCA and stay in business,” says Carlos.