I have been trying to improve the taste of the Coopers Pale Ale kit and have decided to try cultivating the yeast from a 'commercial' Coopers bottle. To do this I did the following.
1. Mixed approx 50grams of malt extract with approx 600 ml of water, and boiled down to approx 500 ml over a 15 minute period;
2. After 15 minute boil period, cooled down to room temperature and added the bottom inch of two Coopers Mid Strength stubbies (I used mid strength as I was advised all Cooopers use the same yeast, and mid is easier to cultivate from due going through a less vigorous fermentation);
3. Sealed jar with stopper and air-lock and waited;
After 2 days there was no visual signs of anything happening ... so I gave a good swirl then put jar into direct sunlight to raise the temperature ... now after 4 days there is a consistent white froth on the top about 5mm in height (looks like the head of a beer), and when I give it a swirl the froth raises to about 1 inch. The mixture and reaction to movement is similar to what you would expect from a beer. As there was no obvious bubbling in the air-lock I'm not sure if I have been successful in recultivating the yeast. ... Does this sound like it's worked? should I wait longer, or am I ok to pitch this into a kit now?
Appreciate any advice.
Forgot to copy URL where I found the opinion below. ie. one person's technique re cultivating...
RECULTURING LIQUID YEAST FROM A COOPERS BOTTLE
Im using the Grumpys one shot sanitiser which is a no rinse sanitiser which makes the process much easier. Wack a litre of water in a large bowl and add a teaspoon of one shot. This is your sanitising solution. Chuck in a small funnel and a thermometer if you want to measure temps. (I didnt bother to measure temps). Take a long neck of coopers, (preferably it has sat in the fridge for a while so the yeast is sitting nicely on the bottom). Using a bit of paper towel soaked in your sanitiser solution that is in the large bowl, liberally wipe some sanitiser solution around the top of the bottle and cap. Then carefully open. Use more paper towel soaked in sanitiser solution to wipe around the top of the bottle. Sit for 30 secs to let it do its thing. Carefully pour the beer into a glass or two trying not to stir up the yeast too much. Leave about 1-2 cms of beer in the bottle with all the yeast. Wack some aluminium foil on the top of the bottle and put aside so that it warms to room temp. Put about 330ml of water in a saucepan and bring to boil. Add 2 heaped tablespoon of light dried malt extract, (30gr). Stir it until dissolved and bring back to the boil. Stir and boil for a few mins then put on simmer and put the lid on. Let simmer for about 5-8 more mins and then put the pot in the sink with some cold water, (half way up the side of the pot), to cool down pot. Leave in there for about 5 - 10mins and carefully change the water once or twice. Remember that what you have in the saucepan is now sanitised so make sure no water from the sink splashes under the lid. I use a small clean 600ml PET water bottle (plastic 600ml coke bottle or similar would do). I put some sanitiser solution in the bottle, wack the lid on, and shake it up so it all gets coated with sanitiser. Tip out sanitiser and drain on a piece of new aluminium foil that I put in the dish drainer on the side of the sink. Put the cap on the foil as well to drain. Pull the funnel out of the sanitiser and also put it on the foil to drain plus the thermometer if you are using one.
When the saucepan is cool to the touch its probably sitting around 24C, which is about right, (check with sanitised thermometer if you want to make sure). I pull the saucepan from the sink and sit it on a tea towel and dry the bottom and sides. This is so that no drips run down the sides of the saucepan when you are tipping out the sanitised wort which may get in your solution and cause an infection, (CLEAN CLEAN CLEAN !!!). Using the sanitised funnel, pour the wort solution into the empty sanitised bottle. Then if the temp of the wort and the yeast in the coopers bottle seem fairly close, swirl up all the beer and yeast in the coopers bottle and pour it in on top of the wort. Put the sanitised lid on and shake like hell to get some oxygen into the wort. Open the lid only just so that any CO2 can squeeze out. Sometimes I leave the lid shut so that you can crack it open every few hours to see if you get a hiss of CO2 which is a good indication that the yeast is growing. Put in a warm place (not in sunlight). You want to keep temp about 22-25C. Everytime you walk past give it a good swirl to get the yeast on the bottom back in solution. Some people dont use the cap and put a rubber bung on the top with a hole in it and a normal airlock in the hole, (another option is to drill a hole in the normal plastic cap, bit a rubber grommet and then an airlock just the same as you do with yoru normal fermenter). You can then see some bubbles but it really is not that necessary. You dont see much action anyway, and it can ferment out pretty quick. The best way to get a feel for it is really to look at how big the layer of yeast is on the bottom. Some people will pitch this first step after about 24hrs if there is good signs of yeast growth. You can probably get away with this but you may get a decent lag time in the fermentor when doing this. In reality you probably want a bit more yeast, so after 24 hours you should step it up to about 600ml, let ferment for another 24 hours and then pitch. To step the 300ml starter up I basically follow the same procedure. Get a CLEAN 2 litre soft drink PET bottle and lid, add a litre of water to this and a teaspoon of one shot. Shake around so that the insides are coating with solution then pour the sanitiser solution into a bowl. Chuck in the funnel. Leave the bottle and lid to drain on some clean aluminium foil. Boil up 600ml of water and four heaped tablespoons of light dried malt extract, let it cool in the sink as per before, add to the bottle, then pour the 300ml yeast starter into the larger bottle. Put lid on and shake like hell for a few minutes. Crack lid a tad to just let any CO2 squeeze out and then give it a swirl every time you walk past. Should be ready to pitch in 24 hours but if your not ready to brew you can either let it sit a couple of extra days, and pitch, or even put it in the fridge, then take out and step up again 24 hours before brewing. When pitching, swirl up all the yeast in solution, tip a couple of capful out into a small glass to smell and taste, and if it smells and tastes all right then pitch what is in the bottle directly into the fermentor. If you have picked up an infection during the process it should smell and taste suss. If this happens its no great drama as you just go back to the dried yeast as a backup and pitch that. Then try and be more clean next time to do it. If you want to try using liquid yeast from a commercial bottle of beer, your only cost is a long neck of coopers and 6 heaped tablespoons of light DME. As per above, if it doesnt work you just use some dried yeast. If you start using liquid yeast you end up with quite a few spare dried yeast packs in the fridge so can use these. Another option is to have a test run just for fun. Keep stepping the yeast up a few times to get a feel for what happens. Taste and smell it at each step up. For about $5 its a
great way to get good liquid yeast and perfect if you are brewing a Coopers copy, as you get that real Coopers taste. The long neck of beer is a bonus. Ill try a Mountain Goat Hightail Ale next. This is probably my favourite aussie beer and the yeast, (I think), is Wyeast 1028, which is a great all round Ale yeast. If you do stubbies youd probably do 2 or 3 of them to get enough yeast to start off.
