Removing Stuck Glass Decanter Stopper

The technique appears on several web sites. It works. The purpose of this article is to document my observations of what happened.

A well machined tapered glass decanter neck with a matching machined glass stopper achieves its seal by achieving uniform and nearly complete surface contact. While it is possible to mechanically jam the two mating pieces of glass, it is more likely that the last pour left some contents on the mating surfaces. This material spread through capillary action and effectively became glue.

The primary approach is to use differential expansion where heat on the glass decanter neck doesn't immediately transfer to the glass stopper and therefore the neck becomes bigger while the stopper remains the same size. This principal is similar to heating a metal lid on a glass jar. Metal expands much more quickly than glass when heated and the metal lid is relatively low mass compared to the glass jar. The result is effective thermal differentiation.

A glass stopper and a glass decanter won't achieve much physical size difference using heat. You don't need much. What you are actually trying to do in addition to giving the stopper less of a mechanical grip by the decanter is to fracture the sugar glue or otherwise offset its bonding power. Remember glass is extremely brittle so applying extremes of heat and cooling on the two respective parts can cause them to fracture. Stick with the recommended tap hot water and do not bother with ice.

BE PATIENT! I tried heating the neck and tapping it with a wooden spoon. I also tried the risky course of brute force. That was a bad idea but my luck held. There was a little water pooling in the seam where the stopper mated with the decanter after I had heated the body of the decanter with the idea of creating some pressure from thermal expansion within the decanter. I saw small bubbles for part of the circumference of the seam meaning the seal was imperfect. That made clear to me that when the body cooled, room air would be drawn into the decanter.

Oil based paints frequently use vegetable oil as their base. When the oil dries, a strong flexible bond results. Different vegetable oils dry at different rates. Most web site articles suggest using olive oil for the next step though some suggest petroleum based products. I made the mistake of using a rice based oil that dried in a few hours. Fortunately what dried was on the outside of the decanter and the oil that was sucked into the mating surfaces remained in its original state. Use olive oil because it dries slower and is not toxic.

With oil sucked into the miniscule gap between a portion of the mating surfaces, capillary action attempts to spread the oil throughout the tight mating surface. Using a wooden spoon to tap the sides of the stopper gently helps capillary action distribute the oil and helps mechanically break the sugar glue bond.

I suggest you heat the base and neck of the decanter under hot running tap water. Dry the exposed seam and place a partial spoonful of olive oil on the seam. Let it sit until the next morning. Then run the decanter under hot running tap water and tap the sides of the glass stopper gently with a wooden spoon with some bulk. If it doesn't release, repeat the steps patiently.