The improved bucket still
The Improved Bucket Still is one of the simplest stills you can imagine using a small electrical heat source, but no cooling water.
The basic principle is simple.
In a 25-litre vessel an ordinary 10 litre plastic bucket containing mash is placed. The lid is placed on the vessel, shutting in the 10-litre bucket. The mash in the 10-litre bucket is heated with an immersion heater to 45-50 degrees C. The air in the 25 litre vessel becomes saturated with water and alcohol vapour. After a short while the spirit and water vapour condenses in the inside of the 25 litre vessel and runs down to the bottom. That’s it! It is no more difficult than that.
The alcohol that condenses out has strength of 35-40% which is the usual strength of commercial spirits. It is possible to make several different versions of the apparatus to give higher strengths, but more on that later. The quality is good, but not absolutely perfect. A little purification with activated carbon is required, and I will explain about that later. Compared with the quality one gets from a usual still, this is much better. If one holds 50 degrees C in the mash, one gets about one litre per 24 hours, which should suffice for the most thirsty individual. 45 degrees C produces a better quality but at a slower rate.
How to make it:
You can use any type of bucket you have available, but keep in mind that it must be something that is alcohol proof, e.g. food grade plastic (PP or PE plastic), stainless steel or ceramics. Plastic items are usually stamped with the type of plastic they are made from. A 60 mm high item is about right. Use a white or transparent plastic item to be on the safe side, ensuring it contains no toxic colours.
I would suggest to check out wine fermentation vessels which are sold by many homebrew shops.
These containers are usually of 30 litre capacity but are usually called 25 litre wine containers or fermentation vessels. In the bottom of the 25-litre container something should be placed to raise up the 10 litre container a bit. I have used a 10-litre bucket that I have cut down to make it about 60 mm high. It is wide and gives good support. (Remember,Make sure there is a hole in the top of item you intend to use so it does not float when alcohol runs down in the bottom of the 25-litre container).
Over this support I have placed plastic disc. This is cut from the lid of a fermentation vessel. Cut the disc so that there are as small gaps as possible round the edge. The disc should be 320 mm in diameter. In the picture one can see I have cheated a bit, but it gives an idea of how accurate it should be. The disc is there to separate the alcohol from the air in the vessel. A nice touch is to order a glass disc from a glazier. This should be more than 4 mm thick and have a diameter of 317 mm with bevelled edges for safety. Cost is about 15US$ / 10 Euros. Such a disc gives a bottom plate that is a perfect fit. Remember to place it high enough to give a tiny gap all around for the alcohol to run past.
There should be 5 litres capacity for the alcohol in the bottom. As the fermenting vessel has volume graduation on the outside it is easy to see how high the disc should be placed.
Now is the time to put the 10 litre container in the 25-litre container. The 10-litre container can be obtained anywhere. It does not have to be exactly as shown in the picture. The 10-litre vessel should be filled with 8 – 9 litres of mash. Preferably use a white container if you are unsure if it has food quality approval.
Then put on the lid. I have cut a hole towards the edge of the lid allowing for the entry of the immersion heater. Preferably use an electric drill, otherwise it is easy to split the lid. The reason for using a fermentation lock is that the air in the container will expand and contract a little, depending on the temperature of the surroundings. If you use a fermentation lock with activated carbon the distillation will be completely odour free, use no water in the fermentation lock, only activated carbon.
The immersion heater can bought in a pet shop. Normally used to heat a fish tank, and is available in various sizes and wattage. There are several different types of immersion heaters that work well with this apparatus. Buy an immersion heater with a thermostat that goes up to 55 degrees C. Unfortunately most of the units sold in pet shops are unsuitable. Unfortunately nearly all thermostats have a maximum setting of 32 degrees C. A thermostat is for regulating the heat of the water. You set the temperature required and the immersion heater then holds this temperature in the water. 32 degrees C is too low and it would take forever to produce anything. A suitable temperature range for this unit is 45 – 52 degrees C.
Then use a digital oven thermometer to indicate the temperature of the mash as it is difficult to know if one has the right setting of the immersion heater.
After you have acquired an immersion heater you need to fix a rubber bung over the flex to seal the entry of the wire through the lid when you fit the immersion heater to the apparatus. Rubber bungs usually already have a hole in the middle. Cut off the flex near the electric plug, put in the rubber bung and re-connect the flex with a terminal block or put on a replacement plug. Seal the hole in the rubber bung with silicon sealant or tape to make it airtight. Alternatively saw through the bung to the hole and slide in the flex, thus making it unnecessary cut the flex.
Start it up!
The immersion heater is in position. Now one only has to plug it in and wait. After an hour vapour forms in the container and then spirit starts to flow down the edges of the vessel. As you will appreciate spirit also forms on the inside of the lid and drops back in the 10 litre container. The strength of the spirits increases somewhat thanks to this. However there is sufficient speed in the drips nonetheless. ½ to 1 litre per 24 hours will be produced if the vessel is kept at room temperature.
Modification 1: To increase the speed of the distillation you can tilt the fermenting vessel. All distillate that condensates inside the fermenting bucket will be removed by tilting the vessel. The product will be slightly weaker but you gain speed up to 1.5 litres a day. This design is great to use as a prestill if you use a fractioning apparatus or potstill. Tilt the fermenting bucket and instead of a false bottom you add 2-3 litres of washed gravel. The gravel will build up a horizontal bottom so you can place your 10-litre vessel upright. On the side of the fermenting vessel you drill a hole and add a hose, this is where your product will be removed.
Modification 2: Another way to increase speed is to dome shape the lid on the fermenting vessel with a hot air gun. That way you can keep the false bottom and don’t have to tilt the vessel. Takes some skill though to shape it.
see also: http://www.plasticstill.com/