How To Fossilise Your Hamster bookI admit I was ignorant of how to go about fossilising a (deceased) pet hamster until I purchased the paperback of the same name. How To Fossilise Your Hamster: And Other Amazing Experiments For The Armchair Scientist (£6.39 on Amazon for the paperback, £4.12 for Kindle version) is a must for anyone who longed to receive a Chemistry Set for Christmas but never did. So if you've got half a bottle of rum, a can of coca cola with the fizz intact and some ice cubes you too can experiment with the contents of the drinks cabinet.

Mix yourself a Rum and Coke cocktail using a dash of dark rum and a classic cola then watch a harmless frothy scum form around the added ice cubes. Taste to ensure the experiment is commencing as planned, then mix another Rum and Coke but using pale rum (Barcardi is suitable but a supermarket own-label will be just as good at two-thirds the price). No dirty looking froth forms this time, but why is that?

Goslings Black RumDistilling molasses, the gooey burnt sugar syrup left over when sugar cane is turned into sugar, produces a colourless and highly alcoholic spirit. Adding back a bit of the dark brown molasses turns this 'white' rum into a sweeter, darker version of the original.

The added molasses contains dissolved calcium and magnesium (the same stuff that furs up the kettle in hard water areas). Adding cola causes a chemical reaction to occur which turns these into solids. These float on the surface of the drink and form the scum which is really difficult to wash off unless you leave the glasses to soak.

White rum doesn't have the added molasses so there is nothing for the cola to react with. Hence no scum and a visually more attractive drink.

Coca colaNow you've experimented with altering the rum component why not change the other constituent part of the cocktail, the coca cola? Hours of fun, I mean scientific experimentation, can be had in analysing the flavour profile and froth index of big brand colas versus supermarket own label; or adding diet, sugar-free, caffeine-free colas, or trying colas with added vitamins or with or without cherry and lemony flavourings to the mix.

Once you're happy the experiments have reached a satisfactory Conclusion (you don't have to record details of the Apparatus, Method and Results in an orange-bound lined notebook unless you wish to but hand in to me for marking if you do) why not transform all these plain old Rum and Cokes into Cuba Librés by adding the juice and hull of half a lime to each of the glasses.

Before the ice cubes melt perhaps I could interest you in one last observation experiment? Had you noticed how there always seems to be bubbles of air trapped in the cubes? No? Well unless you've been using the blemish-free fake plastic ice cubes seen only in billboard drinks adverts then your cubes will be imperfect. All tap water contains dissolved air and this gets trapped as the water freezes.

Class is now dismissed.

(Look on page 151 for instructions on fossilising your hamster.)

PG Supermarket Rum Price Comparisons

rum labelOwn-label dark rums

Asda Dark Rum (1 litre) £15.90
Asda Dark Navy Rum (70cl ) £12
Sainsbury’s Basics Dark Rum (70cl) £10.49
Tesco Dark Rum (1 litre) £15.90
Tesco Everyday Value Dark Rum (70cl) £10.22

Own-label white rums

Asda White Rum (1 litre) £15.90
Asda Caribbean White Rum with Coconut (70cl) £12
Sainsbury’s Basics White Rum (70cl) £9.49
Sainsbury’s White Rum, Lime & Cola (250ml) £1.50
Tesco White Rum (1 litre) £15.90
Tesco Everyday Value White Rum (70cl) £9.49

This article has also appeared as Paula's Wines of the Week on