[Edit Note: For those reading through this thread, my reply below will seem as though I've totally missed the question asked. The original post was a little ambiguous so I assumed that all Ploppa had was the India Pale Ale. Ploppa quickly fixed this with an edit which I just noticed today. Cheers!]
How goes it Ploppy!
Congrats on your first post! Youll find the people on this site really helpful and theres enough info on here to keep you going probably for a lifetime. A good place to start is here.
http://www.aussiehomebrewer.com/forum/Freq...pics-t1151.html
First thing to read is, Two Can Kit Screamers and Beefing Up the Kit Brew.
Anyway, to your question
Brauluvers answer above is absolutely correct but as you say that you are relatively new to brewing Im going to word it a different way.
For a normal kit brew you usually use 1 tin of malt extract (thats your India Pale Ale) plus a kilo of dry stuff such as dried malts, sugar, dextrose etc. These are commonly called adjuncts. So you are going to need.
1.5kg Tin of Coopers India Pale Ale
1.0kg Adjuncts
In your post you say, The instructions say to use 500g of Coopers + 300g dextrose, but Im unsure of what you mean by Coopers. Im guessing when they say that, they are suggesting you use, 1 tin of Coopers India Pale Ale, 500g of Coopers Brew Booster (1 or 2) and 300g dextrose. If so, then this would make sense.
So, I know you definitely have your 1.5kg tin of India Pale Ale. All you need now is 800g to 1kg of dry adjuncts (forget liquid adjuncts in your early brewing so probably and hopefully theres no need for your original question to be answered anyway!)
For your 1kg of dry adjunct, I would suggest that you go to your brew shop and buy a 1kg bag of their Brew Booster. Alternatively, go to the supermarket and buy 1kg of Coopers Brew Booster (No 1 or 2). These contain a better quality mix of dry adjuncts and are all you will need. You wont need any dextrose (dextrose is a pretty low quality ingredient as well).
If you are relatively new to home brewing, before you put this next batch on, try and wait until the weekend which will give you a bit of time to do some more reading.
The best 3 things I can suggest are
1. Buy some household bleach and search this site on how to use it as a cleaner/sterilizer.
2. If you are going to the Home Brew Shop then buy a pack of Safale SO4 Yeast (about 2.75). Just put the yeast supplied by Coopers in the fridge and keep it for an emergency. Safle is a far higher quality yeast. Also, it goes berserk so you will have more fun watching it!
3. Work out how to keep the temperature of your fermenter constant and as close to 18 degrees as possible. I use a 100 Can Cooler from Kmart ($20-$30) and ice bricks. You can use soft drink bottles of frozen salt water instead of ice bricks. Youll only need to change them a few times each day.
Think Ive written way too much!
Cheers mate!
P.S. If Ive totally misinterpreted your question and your Coopers India Pale Ale is left over and you simply want to use it instead of dry adjuncts, then Brauluvers answer is the go! Mind you, if youre only going to use a part of the tin then youll need to store the remainder in the fridge under air-tight conditions.
