Suzanne,

This depends to some extent on where the decanter was made! The imperial fluid ounce is 28.4 ml, the US one is 29.6 (rounded to 3 decimal places which is more than anybody ought to worry about in cooking, serving wine, etc.)

Now, we ask: why do the decanters come in weird sizes? (Fifty-nine-and-an-eighth ounces!?) Answer: Because they are mostly made to metric standards!

25 oz imperial is 710 ml, but 25 oz US is 740 ml. It's probably a 750 ml decanter, labelled to the nearest ounce for sale in the US.

Similarly, 26 1/2 oz (US) is 784 ml but 26 1/2 oz (Imp) is 752ml. Probably a 750 ml decanter for the Canadian market.

50 oz is a US magnum (double bottle, 1.5 litre) 59 1/8 is a US 1750 ml (rather exactly labelled) and 68 oz is a US 2l.

Bottom line: the two smaller ones are probably identical in size and exactly the 750 ml you are looking for. However, if your father prefers red wines with a lot of tannin, you might consider that a decanter holding more than a bottle (thus with some air space) may help the wine "breathe" and improve the flavor. (This is controversial; some wine experts don't think it helps. See the Wikipedia article on decanters. But what does your father think?)

-RD

Suzanne,

There are many pages on the web that perform metric conversions. One such page is World Wide Metric but it doesn't bother with British units. There are many other such pages that you get by googling "metric conversion".

Chris