One of the first things any aspiring maltheads learn is that whisky is drunk by the dram, the act of doing this being aptly named dramming. They will soon find out that the dram is an immensely flexible unit of measure, and this is actually part of the secret why dramming in company is so much fun.
The Easy Answer
For personal use, a dram is just the right amount of whisky that you feel comfortable with at a given moment. The size of a dram can be further specified with descriptors ranging from wee over healthy to stiff. Depending on the disposition, mood of the day as well as level of inebriation of the pourer, these specifications may show a tendency to converge at the stiff end of the scale.
It takes a bit of practice to free-handedly pour consistent drams of reasonable size. As a point of orientation the beginner may use the level where the diameter of the nosing glass is widest, this is usually a decent medium sized dram. It should be obvious that it is not advisable to use this method for straight sided tumblers, or you’d have to fill them right to the brim.
For Those Who Need It More Specific
We could just stop here now, pour ourselves a healthy dram and sit back. But life is not always that easy. Unfortunately the whisky world does not only consist of free-pour drams. If you want to sell your whisky by the dram, things get a tad more complicated.
You have to specify the size of your dram. And often you are not even free to choose a size to your liking but have to stick to dram sizes defined by the law of the country you live in.
Lets start with looking at the word dram itself. It is derived from the Greek drachm, an ancient weight of ca. 4.37 grams. You can see that the Pound Sterling is not the only currency based on a weight. But the pound has always been significantly heavier than the drachm as we can still see today.
In the avoirdupois measuring system, a dram is defined as 1/16 of an ounce which is exactly 1.7718451953125 grams. Now we don’t want to sell our whisky
by the pound by weight, but luckily there is also a liquid version of the dram, called the fluid dram. For some strange reason this is defined as 1/8 of a fluid ounce. As the US and Imperial systems use whackily different definitions for their units of volume, we end up with 3.6966911953125 ml for an imperial fl. dram or 3.5516328125 ml for a US fl. dram. This measure is pretty much on the wee side, it’s not much more than a sip.
In practical pub life, larger servings are preferred, so in the USA the standard measure is a US fl.oz or other multiples of 0.5 fl.oz. As ever so often, things in the UK were a bit more complicated. Unit of choice used to be the gill which being a quarter pint is pretty much usesless in a pub. Way too small for a beer and way too big for an average whisky drinker, a cup of coffee perhaps or a glass of wine. Spirits used to be served in quantities of 1/6, 1/5 or 1/4 of a gill or 35.5, 28.4 or 23.7 ml respectively. A 1/5 of a gill is the same as an imperial fluid ounce. The dram size varied regionally, as a rule of thumb it became bigger with increasing distance to London.
Both the UK an Irleand adopted the metric system in the 1970s (sort of…), the spirits measures subsequently being converted to mililitres. Ireland decided to stick with the large 1/4 gill of 35.5 ml as standard dram, UK publicans have the choice of serving 25 or 35 ml.
Countries with a longer metric tradition are luckily unaffected by this thicket of fractions and decimal numbers. But don’t expect drams served in bars to be the same size all over Europe! Every country has different traditions in serving spirits. In Germany the standard shot size is 20 ml, but whisky is often offered at 40 ml (looks better in the tumbler with ice…), in France it is 30 ml, and so on.
As you can see, even when trying to define a dram as thoroughly as possible, its flexibility in volume is hard to grasp.