FANTASTIC PLASTIC KEGS

When we start out in this hobby, CraftBrewers can be a sceptical bunch. Most will have a lingering doubt that the beer they are trying to make will not be as good as what they can buy. So its not surprising that most will spend as little as possible on equipment at the beginning. And when faced with the option of using kegs or buying bottles to put your beer into; well the choice is clear, "cheap is best because I am unsure of what I can make, so its bottles for me". This is perfectly natural.

It's when you realise that you can make a perfectly good beer that you start looking at the gear you originally bought, and looking at improving your brewing skills. It doesn't take long for the CraftBrewer to realise that bottles are a real pain to use. Bottles take up a huge amount of space, and are very time consuming. Lots of washing, cleaning and stacking, not to mention the time it takes to actually bottle the beer. And when one breaks, or worse explodes then they can even be life threatening. So the CraftBrewer will start looking at other ways of storing and serving their beer. Stainless steel kegs in all their forms are the obvious choice. That is until you look at the price. Firstly the kegs themselves are not cheap, even second hand. Then take into account you need a gas cylinder, regulator, taps and the cost of the keg system goes up. Then you need a fridge to house them and suddenly the kegs the shop is selling for a couple of hundred dollars jumps considerably.

This can put the CraftBrewer off buying a keg, as they either can't afford it, or their experience is still limited and the beers they are making don't justify the cost of the kegs, so they decide instead to stay with bottles. On a side issue this is not justified. Stainless steel kegs are one of those items that don't lose value. You can sell them for the price you initially paid. Actually they are becoming more difficult to find around my area, so I expect their value to increase. For example I bought my kegs in 1995 for $50.00 each. In 2001 they now sell for $90.00. The reason for this is soda-kegs (soft drink kegs) are no longer made in most countries for use in the bar industry, the industry has moved to disposable systems. You can still buy new kegs imported from the USA but they are quite expensive.

OTHER TYPES OF KEG SYSTEMS

Many CraftBrewers don't realise there are quite a few alternate keg systems in the market place. Some of these systems are very good, but almost every type comes from the USA, and by the time they reach other countries they are as expensive as the stainless steel kegs you can buy at the brew shop. These alternate keg systems all have a common thread. They are made out of a cheaper material, normally a plastic of some kind. This brings down the cost. Plus plastics can be moulded to any shape. The one great advantage is they can be made small enough to fit in your existing fridge, (something the large stainless steel kegs cant do) so you do not have to buy a second fridge. Using your existing fridge to chill your beer is a major advantage.

The other great advantage that keeps the cost down is you don't need to hire/buy a gas bottle and other equipment such as regulators and fittings. All these keg systems work off little throw a way gas bottles (soda chargers) that are used in devices such as soda-water dispensers, or those home made soft drink machines you get at department stores. The CO2 source in these keg systems is not meant to gas the beer. The beer gases itself by priming the keg with sugar, no different to a bottle. The CO2 source that you use helps maintain the pressure once you start pouring the beer. These keg systems have a device that allows you to add small amounts of CO2 to maintain the pressure in the keg when you start pouring.

The procedure is:-
1. After primary fermentation is finished the beer is transferred to the plastic kegs
2. You add a measured amount of sugar to the keg
3. Seal the keg and let stand for two weeks to naturally carbonate
4. After two weeks the beer will be carbonated and you put the keg in the fridge
5. Pour from the keg through its tap, adding gas from your CO2 source to maintain the pressure

HOMEMADE PLASTIC KEGS

As I said before, the cost of these kegs can be as dear as stainless steel systems. But there is an alternative. Take a look!

This is a picture of two homemade plastic kegs. They hold about 8 litres each and cost about $30 each including fittings.

It may surprise you that these kegs are the plastic spray bottles you find in the gardening section of any store. They are the ones made of thick plastic that has a pump in the centre of the lid. These containers are designed to take pressure, as you pump them up with a hand pump to spray the relevant liquid. These kegs are food grade plastic, and you can buy them in sizes from one litre to 20 litres, so there is a size available to suit everyone. Looking at the picture try to find one with the following features.

A pressure release value (in this case attached to the lid). This is important to stop the container splitting open if too much pressure builds up.
Note the depressions in the bottom of the container that act as feet. While not important it is desirable to have this as it allows yeast to settle in these hollows and thus be below the pick up tube.
You need an opening at the top big enough to get your fingers in. This is necessary to fit a tyre valve

MODIFYING THE PLASTIC KEG

The first job is to fit a tyre valve to the keg above the liquid line. Refer to the article on Carbonation caps as it is the same procedure. Tyre valves can be found at any tyre place. You need to get the chrome plated ones or if you are lucky stainless steel. You can get these free of charge as the tyre shops, as they constantly replace the metal values in cars tyres with rubber ones because the metal ones don't seal well on many tyre rims. There are always old ones out the back. I have found if you bring in a bottle or two of brew they will even throw in the valves for free. You normally should replace the rubber washer that seals it to the container with a new one available from any hardware store.

Next job is to check the lines. You should take them apart and remove any inbuilt filters. These filters will cause the beer to foam up. It is preferable to replace the line and gun with something more suitable for beer.

YOU SHOULD CHANGE THE FITTINGS

I have found that in many of these containers the fitting do leak over time. After all the original fittings are not designed for long-term pressure use and many will slowly leak. What I recommend is you remove all the original fittings and replace them. Buy some hoses from your brew shop (or use the originals if they are ok) and get the shop to crimp them on to the keg. As for the tap, there are plenty of cheap plastic $2.00 taps used in urns that will do the job nicely. Fit one of those as a tap and again get it crimped at your brew shop. The keg pictured has the original gun and fittings that worked for about 3 months then developed leaks. At the end we replaced the lines and tap for $5.00, crimped them on and stopped the leaks. An alternative to crimping that works just fine is to wire tie the fittings with a bit of stainless steel or copper wire. All you do is wrap it around the fitting and twist it tight.

Next job you need to do is to modify the pump mechanism. I do not need to go into a long explanation about not pumping air into your beer to keep the pressure up. The air will oxidise the beer, give off flavours as well as introducing micro-organisms that could infect you beer. But another valid reason is the pumps use grease as a lubricant and that will affect the taste of your beer. The pump mechanism is no different to a bike pump, but it is built into the lid.

To modify the pump you remove the pump mechanism from the lid. Take out the pump handle and throw it, you don't need it. Clean out the grease out of the pump housing. At the bottom of the housing you will find a one way valve. Generally they should not leak but like the hose fitting they may over time. I would remove it and seal the hole with a screw and a washer. Another way to seal the valve is to use a food grade glue. This is what we have done in this example. Either way, seal the pump, clean it and that all that you need to do to the container.

SUPPLY OF CO2

The final item needed is a source of CO2 for your keg. What we need to take advantage of is a cheap easy source of CO2 that is readily available. What is used in this example is the soda-stream dispenser that takes a small CO2 cylinder available in most department stores. All you do is modify the dispenser by fitting a tyre valve.

These dispensers can be bought new, but they are also found in almost every second hand store and garage sales. They are quite common. Other methods I have seen are modified soda bottles and cream dispensers that take those small soda CO2 cylinders. I have even made special fittings for soda stream cylinders that just screw on. The sources are endless. The aim is the same regardless of what you use. All you are trying to do is get CO2 from those disposable cheap CO2 sources into you keg through a tyre valve.

Here is the system all together ready to go. From left to right, you can see the modified pump housing that has been sealed, the container with the tyre valve and the soda-stream maker that has been modified to gas the keg. Now we are all set to use the keg.

USING THE SYSTEM

Lets start with cleaning the keg. There should be no need to ever unscrew the main lid.

All access to the keg should be through one opening only and that is the pump housing. Never scrub the keg as it will scratch and these scratches will harbour germs. The kegs clean very easily with either a hot caustic solution or bleach. Just add the solution and hot water and seal the keg. Make sure it gets into the top and run it through the line as well. You can leave the solution in the keg till you are ready to use it.

To use the keg first make sure it is rinsed thoroughly to remove all traces of the cleaner. Don't forget to rinse the line. Next you will need to prime the keg with sugar. This will depend on the volume of the keg, but a heaped teaspoon of priming sugar per litre of beer is not a bad place to start.

Transfer your beer to the keg after it has finished primary fermentation. Let the plastic keg sit at your fermentation temperature for about two weeks to build up pressure. After two weeks it can be used when you wish, just put it in the fridge to chill. Remember don't shake the keg up as it will have yeast in the bottom just like when you bottle.

As you pour your beer it you will notice the pressure will drop and the pour will slow. This is when you will need to put more CO2 into the keg to maintain the pouring pressure. This is when you use the CO2 source, whatever it is. Now do not overcharge it. Just give it a short injection to maintain the pouring pressure.

POINTS TO REMEMBER

You WILL HAVE teething problems. Don't expect it to be perfect first time. Getting used to the system will come with practice. You may have to add more - or less priming sugar, or adjust the blow off pressure of the relief valve depending on your system the get the right pour. Getting used to how much gas to add will be hit and miss for a while. But after a couple of brews you will get the hang of it.

Common problems unique to this system that must be dealt with are:-

Keg does not gas up
Add more priming sugar, check for leaks, the relief value is too far out and needs adjusting
Beer comes out too foamy
Too much pressure in the keg, adjust release valve and check if there is a filter in the line that is fizzing up the beer, you may have missed one.
Beer is cloudy
Pick up line is in the yeast cake, remove a centimetre, or the keg may have been shaken up.
Beer tastes funny out of the keg
Not cleaning the keg properly, not sanitising the keg properly, and not rinsing the keg properly.
By the time I get a decent pour, the beer is almost flat
Lengthen the length of the serving line so it takes more pressure to serve the beer.

This example of a plastic keg is not the perfect keg system. It's a compromise of materials that are currently available and cost.

Plastic by its nature cannot take a great deal of pressure without splitting. The carbonation may for some be on the light side. However with the reality that stainless steel kegs will become rarer and dearer, plastic kegs will become more common. This is one option to consider.

Shout
Graham Sanders