I’m getting close to kegging Bure Gold so I needed to clean and passivate the keg, and it makes sense to do all the new stainless stuff in one hit with as much re-use of chemicals as possible. But first everything has to be squeaky clean.
Cleaning
I filled the B40 with 10 litres of water from the warm tap at around 37 ℃ and added 50g Trisodium Phosphate, mixing it with a plastic spoon while circulating gently. Approximate ratio of TSP to water was therefore 5g / litre, which is the lower end of the 5 – 10g / litre ratio advised by the simple instructions printed on the small bottle which arrived with the B40.
The stainless components which make up the centre tube, sparge hat, and all parts of the steam condenser were carefully placed into the malt pipe and lowered into the B40, which I then topped with the steam hat fitted with CIP adapter and ball. The CIP was plumbed to the ‘out’ pipe and the valves set so that the main vessel pumped straight to CIP, picking up from the dip tube on the right. Periodically I’d switch the lower left valve so that the CIP shared the flow with the chiller, ensuring that too had a healthy rate of cleaning. I let that circulate for about 45 minutes before transferring the TSP solution to my 19 litre Cornelius keg, the SS Brewtech Mini Bucket, and the Mangrove Jack’s 5 litre mini keg. The B40 was then rinsed out several times until the water ran clear.
Passivating
The process of passivating all stainless surfaces in order to build up protection against corrosion calls for a ridiculous amount of Star San. I’d heard that you can also use Citric Acid to do the same job, so when I saw some for sale at B&Q I decided to take that route – would be cheaper and kinder to the environment as well. Unfortunately there’s not much info out there on the ratios to use. The back of the packet recommended that when de-scaling dishwashers (among other things) you should add half the pack to the detergent drawer and the rest to the machine itself before doing a normal wash.
I don’t know how much water a dishwasher uses during a normal cycle, but I felt that were I to fill the B40 to the brim then that would be considerably more. After some head-scratching I opted to fill her with 25 litres of water and add the whole 250g box of Citric Acid, figuring that it made for a nice ratio of 10g per litre, and that 25 litres was closer than 40 litres to what a dishwasher would use. This also meant that most of the trainees fittings in the malt pipe would be submerged, while the CIP ball again should keep everything else constantly exposed to the solution. As per previous cleaning step I periodically switched the CIP over to the chiller so that too was covered. The only thing I did differently this time around was to use the heater in order to maintain temperature at 50 ℃, figuring that since I’m letting it run the full 60 minutes I might as well maintain temperature – again mimicking the dishwasher.
