Reculturing Coopers Bottle Yeast

By | April 13, 2011


Welcome all. Yeast plays an important part in any brew, often understated. I recently decided to make a Coopers Pale Ale style beer and getting the yeast right is crucial for getting the same character as this beer. We get the benefit of yeast remaining in the bottle and Ill show you how its of more use than just making the beer cloudy.


2 stubbies should do the job here to get it up and running. Sanitation is the most important thing here so dont drink it straight out of the bottle. Grab your favourite glass and pour it into it stopping when you see the sediment start to run up the neck.

This should result in about 20% of the beer still in the bottom of the bottle. After pouring quickly screw the lid back on to stop any bacteria getting in. Do this with 2 bottles and let it stand out of the fridge and allow it to rise to room temperature.


We are basically making a mini homebrew here so get a saucepan and boil 600ml of water. Take it off the heat and pour in 60g of light dried malt extract. This will give you a wort of approx 1.038. Put it back on the heat stirring well to remove clumps and so it doesnt burn to the bottom of the saucepan. Bring it to the boil for 5 minutes to sterilize it and turn off the heat. Pour it into a sterilized jug with a spout to make pouring it easy and put it in the fridge to cool it to 24 degrees Celsius. (I made 800ml water to 80g light malt extract and used 200ml for a SG test).


For this I used a 1 litre glass water bottle, however using a 1.25 litre Coke bottle or equivalent will work well also. Rinse, clean the bottle well making sure there is no crud of any sort in the bottle, a bottle brush can help this however soaking a low concentration of Napisan with water will see most crud gone. Put some no rinse sterilizer in the bottle (I use brewshield) and shake it to cover all surfaces and let it sit until the bottle is needed. I used a stick on fermenter thermometer to the bottle so I can monitor the temperature.


Once your wort has dropped to 24 degrees in the fridge, tip the no rinse sterilizer out of the fermenter bottle (and rinse if you use a sterilizer that requires rinsing).

Carefully pour the 600ml of malt extract mix into the bottle. Get the 2 Coopers Bottles and give them a quick swirl to mix the sediment up and pour them into the fermenter bottle too. If you have a soft drink bottle you can now screw the lid on and just loosen it every now and then to release pressure, however Ive used a piece of glad wrap held on by a rubber band.


You should do this starter 4 to 5 days before the time you plan to pitch the yeast.

Keep it at around 20-22 degrees Celsius during the bottle ferment. It will take about 2 days for the yeast to wake up and start fermenting in the bottle. You will see a layer of foam form on top when it starts and after a couple of days of this you can pour it into your main batch. Give it a good swirl a few times a day (dont shake) to mix the yeast in and do this also before pitching it into your brew. Once in your main batch brew keep it at around 18 degrees for best results. Please before pitching it into the main brew just pour a little of it into a glass and give it the sniff and taste test, if its rancid, dont put it into your brew.

Hope this article was of help.


Culturing-Yeast-and-Using-Slants (PDF)