anybody know who sells coffee essence in Adelaide, South Australia?

You can always use real coffee beans, ground very coarse. About a 1/4lb for a 5 gallong batch for the last few minutes of the boil will give anything a pretty strong coffee flavor.

On one batch I added 1/2 lb for the last ten minutes, and I ended up more with beer flavored coffee than coffee flavored beer, but it's all a matter of preference.

Ben

I would recommend using actual coffee beans, preferably from a good mid to low acid coffee (Sumatra, Columbian, Java, Kenyan, etc). The higher the acidity of the coffee, the more you are going to lose the taste aspect from the hops.

Also, I would recommend purchasing freshly roasted coffee rather than what you would buy at your corner market. If you have a local roaster, give them a call and see if you can arange the purchase of ~1/2 lb of coffee. Not only would you be guaranteed fresh beans, but they should also be a great source for info on relative acidity levels of their beans. You may luck out and find a roaster who is also a home brewer.

Personally, I am more fond of the lighter roast rather than the darker roasts, but it will depend on what taste you're looking for. Darker roast coffee will lend more flavor from the roast than the bean; lighter roasts get more flavor from the bean than the roast. But bottom line is pick a coffee and roast you like.

I did make a batch of Brown Ale (recipe was to be similar to Newcastle) and threw in almost 3/4 lb of Kauai Peaberry, which is a somewhat higher acid bean, in the last 5 minutes of boil. I would not recommend having the beans in the boil any longer than 5 minutes; the longer the extraction, the more bitterness you will encounter and the more acids you will extract from the beans.

The batch turned out OK, but in retrospect I should have used Sumatran or Java and somewhat smaller amount of coffee. The coffee taste was definitely there ... and so was the alcohol (~8%).

One last thing. If you do use beans, get them ground course (along the lines of the grind for a percolator or a presspot) and I would recommend placing the ground beans in cheesecloth or boil bag (kinda like making a large "teabag"). It will keep the vast majority of the grounds out of the mix after the boil.