When to add campden tablets
There are 3 times when you need to add campden tablets to you wine making.
The First Time to add campden tablets is at the beginning of wine making. Lets say you have just added your fruit to your bucket and have poured boiling water over it. Once it has cooled to 20°C, add 1 crushed campden tablet per 4.5 litres of wine must, then stir. You can also add your pectolase at this stage.
Campden tablets do 3 things at this stage,
A - they stop bacteria and yeast from multiplying. They dont actually kill them.
B - they prevent your wine must and fruit from oxidising. They suck up all the spare oxygen that is dissolved in the water and fruit juices.
C - they create sulphur dioxide. Due to the reaction in B, they create a gas that’s heavier than air, so sits on top of the wine must. If you breathe in sulphur dioxide as soon as it hits your mucus in your nostrils or your throat, or your lungs, it turns in sulphuric acid. It will make you cough. But this is what creates a protective barrier and will stop things like wine fly from getting to your wine must in introducing an infection.
After 24 hours the effects start to diminish but that’s when you add your yeast. You add enough to start a fermentation. Quickly the yeast you have added will create some alcohol. This is then enough to kill any bacteria that might have been present. The yeast you have added will become the dominant yeast in your must and will do all the hard work of converting sugars to alcohol, but the wild yeast will come back from hibernation and will do their funky things in the background.
The second time you need to add campden tablets is when the fermentation is complete and you are wanting the wine to clear. When the wine has finished fermenting and the sg is below 1.000 it’s best to add a campden tablet to help knock out the remaining yeast. Adding the campden tablet at this stage makes any remaining yeast more susceptible to the alcohol, which will help to kill them.
So rack the wine off the sediment into a clean sterilised demijohn, add 1 crushed campden tablet per 4.5litres (1gallon). Pop in the airlock and transfer somewhere cool to clear.
The third time to add campden tablets is when the wine is clear and ready to bottle. Adding them at this stage helps to prevent oxidisation, helps to prevent the vinegar bacteria getting a grip on your alcoholic wine and turning it to vinegar, and together this helps keep your wine fresh in the bottle.
If you are planning to lay down your bottles for a year or two, especially if you are ageing red wines for many years, adding a campden tablet at the bottling stage, really helps to preserve the flavours, colour and body.