Aha. But I have the answer.
Many years ago, I was being recruited for a job. The recruiting company put me up in a very 10 star swanky cottage hotel, in Wales. This was around 1980 and the wine list started at £60 a bottle! Two guys discussing buying Oil Wells sat discretely over the room from us. We had a wonderful dinner but the wife got hiccups. The wine waiter noticed and came back with wine glass which contained a small amount of light brown liquid. He had a beer mat on top of the glass.
His instructions to my good lady were to lift the beer mat and drink the liquid immediately in one swallow, you must not sniff or in hail just throw the liquid back quick as you could.
It cured the hiccups immediately – the liquid, oho, it was brown vinegar.
Kindest regard – vasbyte
David