Why does silver smell like garlic?
When sterling silver tarnishes, it sometimes produces a smell resembling garlic. This is due to a chemical reaction between the silver itself and sulphur containing compounds in the air or in food, such as hydrogen sulphide or methionine in eggs.
When these compounds come into contact with silver, they form silver sulphide. This chemical, being a sulphuric compound, smells like, you guessed it, sulphur.
Garlic is the most sulphur dense edible food there is, therefore it's not actually garlic you’re smelling on your silver, it's the sulphur.
The more your silver comes into contact with sulphur rich substances the more tarnish develops and more of this sulphurous smell appears.
Overall, silver sulphide is responsible for both the darkening of silver and the garlicky odour on your silver jewellery.
What is silver tarnish?
Silver tarnish comes in two primary flavours.
The first is silver sulphide, a smelly black solid that appears on the surface of sterling silver items when the alloy reacts with sulphuric compounds.
The second, and more visually, but less olfactory prevalent is copper(I) sulphide (Cu2S). Sterling silver is 92.5% silver and 7.5% copper, this copper reacts more readily with sulphuric compounds causing a black tarnish.
How to remove silver tarnish?
So, you have some dark, garlicky silver and you want to get rid of it? You just read on, you crazy diamond.
Jewellers use jewellery pickle to remove oxide layers when finishing a piece of silver, however I couldn’t find it online for less than a tenner and if I were you, I wouldn’t pay that, I would instead keep reading this article and work out how to remove it with simple at home items.
Aluminium foil and baking soda method
1. Put the kettle on
2. Place a sheet of aluminium foil in the bottom of a container
3. Add your silver pieces onto the foil, make sure that your pieces are touching the foil, contact is required for the electrochemical wizardry about to take place
4. Add exactly 3 tablespoons of baking soda into your shiny cauldron. Any more or less will make your silver explode (JK lol)
5. Flick the kettle on again because it’s been 30 seconds since it boiled and you don’t trust that the water’s still hot.
6. Pour in your boiling water just enough to cover your pieces and dissolve the baking soda
7. Leave the silver in the cauldron for about 5 minutes, or until your silver is adequately reinvigorated
How does aluminium and baking soda remove silver tarnish?
CHEMISTRY, more specifically ELECTROCHEMISTRY
The method for cleaning tarnished silver using aluminium and baking soda works through an electrochemical reaction. The tarnish, on silver is silver sulphide (Ag₂S) and copper sulphide (Cu2S), when the silver is placed in a solution of baking soda and in contact with aluminium, electrons flow from the aluminium to the silver and copper, breaking the bonds between the chemicals and reducing the tarnish back to silver and bonding the sulphur to the aluminium. Baking soda increases the solution's conductivity, helping the electrons flow, facilitating the reaction.
Tarnishing silver can be a cool way to change the colour of your jewellery, in the jewellery biz we tend to use Liver of sulphur which is a mixture of the 4 sulphur brothers, potassium sulphide, potassium polysulphide, potassium thiosulphate, and potassium bisulphide (thanks wikipeadia). However these are pretty nasty toxic chemicals which can irritate your eyes skin and lungs (better leave it to the pros).
How to tarnish silver at home with high sulphur foods?
What foods are high in sulphur?
As we have learned, silver sulphide is the chemical that gives oxidised silver its classic colour. As such things with sulphur in them, like that nasty stuff described above, will darken it.
Egg white
Egg whites contain, amongst others, 2 sulphur rich amino acids, methionine and cysteine, thus, when added to sterling silver, should react and create silver sulphide and copper sulphide.
Mustard
Mustard is a cruciferous vegetable, in the same family as cabbage and broccoli these plants contain glucosinolates, which are rich in sulphur, thus should theoretically tarnish silver.
Black coffee
Coffee contains methanethiol, a sulphur containing compound that again, should, tarnish silver.
Peanut Butter
Peanuts are high in sulphur, peanut butter is made of peanuts, you get the gist
Garlic
Garlic contains more sulphur than any other edible plant, silver sulphide smells like garlic, this seems like a match made in heaven for tarnishing silver.
Experiment time!!!
I cut off 5 identical pieces of sterling silver wire and dropped them into each substance for 24 hours.
Before
After
Verdict
Egg wins, no contest, there were a few spots of light browning on the coffee and garlic and no change with mustard or peanut butter.
If you want to tarnish silver at home, boil an egg, crush up the white into a paste, add in your jewellery, nuff said.
THX <3