Using P E T Soft Drink Bottles

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Bribie G

Adjunct Professor
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PET: The Manual V.1.1.1 :lol:

I had been out of brewing for 15 years and on returning I decided to use 2 litre PET bottles:

  • To avoid the arduous task of bottling with the old 750ml 'tallie' glass bottles.
  • I do not have the facilities or finances to go into kegging for the time being.
There is no 'central' point I can find on the forum for PET bottling. I have had to pick up everything myself from scratch over the last couple of months with some valuable tips from forum members of course, and I thought that a comprehensive 'tutorial' might help new brewers so they don't have to re-invent the wheel. The mods may feel that this thread could make a good 'sticky' in this kits & beginners sub forum for a while and see how many hits.

Of course to experienced brewers a lot of the following will sound like the bleeding obvious, :rolleyes: but includes a lot of information targeted at people who are absolutely new to the craft, but bottling time has always been the major turn off in home brewing and hopefully this tute will help beginners get off to a flying start and be confident of their results. When discussing sanitising, priming etc. I have tried to keep it PET specific.

Any comments and suggestions are most welcome.


PET bottles have advantages over traditional glass:

  • Quicker to fill and cap without the need for a capping tool or use of crown seals.
  • Easier and cheaper to obtain than glass bottles
  • It is possible to check the progress of carbonation. Over-gassed (volcano brews!) can be rectified by bleeding off excess gas, which is impossible with glass bottles.
  • Clarity and colour can be checked perfectly.
Disadvantages include:

  • Larger volumes per bottle which may not always be appropriate.
  • The fact that, for beer, they shouldn't be used for very long term storage as they are slightly porous to CO2 in the presence of alcohol and special 'layered' bottles are available for beer use. But for 'quaffing' beer to be consumed within 3 months recycled soft drink bottles are fine and I am getting great results. Commercial PET beer bottles have been around in the UK since the 1980s and do a good job, but have to handle long shelf lives of up to a year in the retail environment .
  • The bottles are clear and in the case of soft drink bottles are not UV layer 'shielded' so need to be kept in the dark to avoid 'light strike' or 'skunking' of the beer.

To be balanced, of course I should point out that 750ml PET bottles made specifically for home brewing are available for around $32 for a batch to fit a standard 23 litre brew. This forum post refers to PET soft drink bottles which start at $11.90 for a 24 litre brew. However a lot of the hints and tips in this post can be transferred to usage of the 'dedicated' PET bottles as well.

For ramping up my initial production I bought a couple of trolley loads of ALDI two litre Regal Cola which comes in cases of 6 for 99 cents per bottle. The cases are worth their weight in gold as an entire brew can be labeled on the case, stored and shifted around in just two cases. I brew to 24 L therefore 12 bottles. (For usage of smaller bottles such as 1.25 or 1.5 L bottles, scale any instructions such as priming rates accordingly). I am aiming to use each bottle for 10 brews which adds five cents per litre to the cost.


Initially I just pour the cola down the laundry sink (massive fish kill in Moreton Bay), rinse twice with cold water, recap and store till required. I do not sterilize further on first use of a batch of bottles as the cola was sterile and the tap water is perfectly safe, in my experience.

Golden rule no. 1:


Brews 1 to 4 were perfectly carbonated. From brew 5 onwards I started to hit the odd 'dud' or leaking bottle. I put this down to my 'high speed' method of emptying the bottles, pouring six at a time down the sink, rinsing in bulk and recapping. Bottles and caps became mixed up and although I don't know how they were originally 'mated' at the factory I am now convinced that the original cap should never be separated from its bottle.


Golden rule no. 2:


On serving a beer (usually by carefully decanting into a 2 or 3 litre serving jug) I never ever have a taste until that bottle has been thoroughly rinsed to get rid of all sediment etc. I do three cold agitated rinses and one very hot rinse. Never put boiling water into a PET as it will destroy it. Leaving the bottle overnight without cleaning "she'll be right" will produce yeast rings etc and you run the risk of infections.

Just a thorough rinse leaves the bottles sweet and I have not had a problem storing them for up to two weeks waiting for next refill but they should be sterilized before actual filling.

On bottling day I make up a quarter-strength cheap woolies bleach (not the lemon!) and rinse out the bottles with this a couple of hours before refilling, leave for a while and then rinse twice with plenty of cold tap water before the actual refill, to remove the chlorine. Other sterilizers such as Sodium Metabisulphite are available. I find bleach is great.

Some forum members would recommend a further rinse with boiled cooled water to remove even the trace of chlorine from the tap water.

Storage: After bottling the beer must not be exposed to light. I get a few spare cartons from ALDI and cut out rectangles to cover the 'slot' in the tops of the cases, and store cases two high.


Most bottlers use a hollow pipe that fits into the tap of the fermenter and reaches to the bottom of the bottle. When it presses against the bottom it pushes a valve at the bottom of the pipe allowing the beer to run. Lowering the bottle immediately shuts off the flow. Excellent and accurate system.


These filling pipe and valve 'sticks' are just fine for PET use and most will easily reach the bottom of the bottle. However if you buy one, take an empty bottle to check as there are a few brands of 'stick' out there. I bought a Brigalow brand stick and it was too short, so check first.

For those who came in late, on bottling the beer needs to have a small amount of extra sugar (of some type) added so that it ferments out in the bottle to yield Carbon Dioxide. As the gas has nowhere to go it stays in solution in the beer to give 'fizz'. Australian and International style 'lagers' suit more fizz than beers such as English style bitters.

Carbonation drops (lollies) are convenient but expensive. Using the priming rates on the Coopers site you can calculate that a 2 L bottle requires five carb drops. However I have found four drops to do the job just fine, with 3 for English style bitters or milds.

  • Sugar cubes are a far cheaper option and miraculously the cubes fit exactly through the tops of PET bottles. They come in boxes of a hundred at Woolies etc. (not ALDI). I find that three cubes give around the same carb rate as four lollies.
  • Bulk priming requires a spare fermenter to use as a bottling vessel where the required amount of sugars are mixed with the beer in one hit, so individual doses do not need be added to each bottle. This actually brings the cost of priming sugars down so low that over a year the vessel will pay for itself several times over. Also many brewers prefer to use Dextrose or Light Dried Malt Extract to prime and for that, bulk priming is a must.
One superb advantage of larger PET bottles is that the progress of carbonation can be checked by squeezing the top area of the bottle where the gas space is and feeling for the amount of 'give' in the plastic. After a few brews you will get a very good 'feel' for progress of carbing.


Especially in winter you might bottle too early and end up with a badly overcarbonated or 'volcano' brew. Fortunately PET won't shatter and shower you with glass but will eventually split. If your brew after just a few days has made the bottles suspiciously rock hard, it's a good idea to chill a bottle, carefully uncap it and check. If it froths up violently then:

  • chill the whole batch
  • over a one hour period gently 'crack' each seal. This will release a rush of gas then the foam will rise quickly. Seal tight before the foam reaches the top. You might need to do this up to ten times, and again a few days later. A pissoff but you can save the brew. This happened to me the first time I used a Saflager yeast after just using the fairly quick kit yeasts previously.

After about four or five days carbing, 'feel up' your 12 bottles :wub: and it will be immediately obvious if you have got a dud or leaking bottle top as it will have a very soft feel. I have had about 5 in 12 brews. Here's how to fix it. After about ten days in the bottle most of the priming sugar will have been fermented out and seeped out through the leaking cap. The beer should still be perfectly sound but flat. Take a 'trusty' sterilized bottle and put four carb drops in. (I keep a jar of drops just for this purpose) and gently pour the beer from one to the other. As you have let the beer go flat you shouldn't get any frothing (chilling first is a good idea) and make sure some of the sediment goes over as well to provide a good dose of yeast cells. Seal up, chuck the dud bottle and the new bottle should carb up nicely. I haven't had an infection from this yet.



If the general public is not going to see your bottles, why remove the labels. However if you are picky about this, or are taking bottles to friends etc, it will be necessary to remove the stubborn glue strip that remains on the bottle when you peel off the label.

Soap and household cleaners won't do it but eucalyptus oil is great and washes off with dishwashing liquid. Depends how far you want to go.

Happy Bottling and Drinking! For further info on priming, fining (clarification) and sterilizing there are numerous topics on the forum.

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