I have been using a home made chiller coil to bring down post-boil wort to as low a temperature as I can in as quick a time as possible. I can get wort temperature down to 30°C or so in about 15 minutes. The hot water produced is saved to wash up later. The last few degrees are reduced by putting the filled FV in a fridge - but that still takes time. So to help the initial temperature reduction even quicker I have built a stand to hold an ex-pub chiller unit and a modified carbonated drinks pump - donated by a friend who was refurbishing his pub - and a selection of garden hose fittings and diverting switches (see picture). The chill bath has been tested and it does produce an lot of condensation - hence the large drip tray set below the whole rig. The idea is to switch the tap water through the beer chiller coil as normal and save the hot water produced in this first stage. Then when the temperature has reduced to a suitable value - shown on the Boiler Temperature Gauge - I can then switch the flow to prime the pump and then close the loop so the water in the system first circulates through the Chiller Bath coil and then the coil in the boiler. If the initial chill of the beer using the tap feed is low enough then the last 5°C should be fairly quick. The Chill bath is currently filled with water and it gets down to 2 or 3°C. If this proves to be too warm then I will have a go with some Propylene Glycol. I have never used that yet so it is an experiment I have yet to try. Has anyone out there experience of using it? I would be interested to know. This may not work of course but I will give it a go on my next brewday - probably next week.