Sterilizing Bottles and Stoppers
All bottles and stoppers must be thoroughly washed in warm water. If, when bottles are held to light, evidence is seen of yeast stuck to the bottom or sides, they should be soaked in a medium-strength solution of water and domestic bleach, such as Brobat, for an hour or so. They should then be rinsed free of this with repeated doses of water. All bottles must in any case be treated with sulphur dioxide solution made up as follows. This is cheap, effective and ensures that any wild yeast or bacteria lurking in the bottles waiting to ruin your finished beer are destroyed.
Get 2 oz. of sodium metabisulphite, or potassium metabisulphite (there being two forms) from any chemist for about nine-pence and dissolve this in half a gallon of warm water. Try to use a glass-stoppered bottle for this as it keeps better than in one with a cork. This is sulphur dioxide gas in solution. When bottle time comes along, half fill the first bottle, shake it up while stopping the neck with the thumb and then, using a funnel, pour into the next and then the next and so on. This half pint or pint will do a dozen bottles; afterwards, it may have lost its strength so throw it away. There is plenty left in the half-gallon jar to do several more dozen bottles. The stoppers should be soaked in enough to cover them for ten minutes or so.
Having sterilized the bottles they should be rinsed with boiled water that has cooled enough not to break them. Some writers on wine making assert that boiled water at this stage is not necessary, but it is, because water quite often contains wild yeasts which boiling destroys. The stoppers may be shaken free of the solution - no need to rinse them unless you want to. When bottling, I merely fill each bottle, take a stopper from the solution, give it one flick from the wrist and then screw it home.