WARNING: Caustic Soda (Sodium Hydroxide or NaOH) is a dangerous chemical and can cause serious injuries when not handled correctly. Always take precaution and wear protection like gloves and glasses when handling Caustic Soda. Never add water to Caustic Soda crystals, always the other way around.
Here in South Africa home brewers are very limited to cleaning and sanitizing agents, unlike our US counterparts we do not have access to the home brew chemical Starsan or to other specialised cleaning chemicals. Sure we can import these chemicals but that will just come out to one ridiculous price.
One chemical we do have access to is Sodium Hydroxide (NaOH) or more commonly named Caustic Soda. Caustic Soda is widely used to produce soap and also does a good job at cleaning out your drains and does wonders for cleaning your home beer making equipment.
Caustic Soda 30% Solution
Take 2l of cold water and pour it into a pyrex or stainless steel pot, do not use normal glass as this will shatter seeing as when the caustic soda reacts with water it get boiling hot. Next add 500g of Caustic Soda crystals, obtainable from supermarkets or hardware stores, to the cold water. Wait for the solution to cool down and pour it back into a plastic bottle, this will now be an approximately 30% solution and can be used to clean fermentation equipment, beer kegs, beer lines ect.
- Fermenter: Dilute 4ml of the solution per liter of water, warm water is better, and let it stand overnight.
- General Cleaning (excl Aluminum): 4-10ml of the solution per liter of water, warm water is better, and let it stand overnight.
- Kegs: Pour 100ml of the solution into the keg and fill the keg with water, leave it overnight and then rinse 3-4 times with water before use. Alternatively you can just pour 30ml into the empty keg and top it off with 2l of boiling water, turning the keg in a different position every half hour to ensure the mixture gets into all the crevices of the keg. You can leave the mixture in the keg until you are ready to use it, just rinse with boiling water before making use of the keg.
- Beer Lines: Its recommended that you clean your beer lines every three weeks, this usually goes hand on hand with cleaning your kegs, when your done cleaning your kegs leave the solution in the keg, apply some presure to the keg and simply push some of the caustic soda mixture through your beer lines.
Please take care when handling Caustic Soda, never pour water directly onto the Caustic Soda crystals, when you get some of it on your skin wash it off immediately, you will know its off when your hands don’t feel soapy anymore. As with any chemical, use it in a well ventilated area.
The solution can be kept in a plastic bottle for long periods and should last you quite some time. This article was adapted from the SouthYeasters Caustic Soda cleaning guide.