Welcome Shindiger!
Firstly, your LHBS owner sounds as though he wants to sell you more kegs! There is no Taboo whatsoever on forced carbonation of a keg.
There may be slight distinctions between a forced carbonated beer and a naturally carbonated beer but most people would be unable to detect these and even so, such a consideration is totally irrlevant except perhaps at the highest brewing level where, depending on the beer, either method would be correct. So, forget your LHBS's advice. There are far more important things to worry about in brewing a good beer.
You've also been given some great advice above but it might seem a little bit hard to follow. In fact, I actually started to write here a step by step process for you but can't really do so properly without knowing what equipment you have, what process you have used and what ingredients such as kit or grain that you started with.
I might as well have a bash though as it's either writing a reply to you or doing tax paperwork. Think, think think.... Yep, let's write a really detailed answer to your question - much more fun!
Firstly, I'm going to assume that you don't have heaps of kegs that you can afford to leave lying around without them dispensing beer.
I'm also going to assume that you have aged, if necessary, your beer correctly and now have it sitting in a, 'cube,' that has been sitting in your fridge at 2 degrees for at least 14 hrs. I'm aslo going to assume you have a clean keg. If so, you can be drinking beer in half an hour.
My last assumption is that you want a lot of detail - lol!
1. Put a litre of no-rinse steriliser in your keg, put the lid on after giving that a spray with steriliser and swirl everything around.
2. Connect your gas line and the liquid line that runs to the tap to the keg. Open your beer tap and put a jug under it. Turn on your gas bottle and turn the regulator knob until you can hear the gas running through. When you see the steriliser coming out your tap, turn the tap off and then the gas bottle. Wait ten minutes.
You now have a keg full of CO2 so no need for purging. You also are sanitising your beer line and tap.
4. While the above is going on, pull your cube out of the fridge GENTLY and put it on a bench. Tilt the cube so that wherever you are going to be sucking the beer from (tap, syphon or, better still, $16 auto-syphon) is at the lowest point.
5. Open beer tap and let all steriliser run through until you are just getting CO2 coming from the tap and a few dribbles of steriliser. (You may need to turn gas on again to do this but probably not.) Disconnect gas and liquid lines from the keg.
6. Syphon beer from cube into keg. If you're paranoid, cover keg and cube opening s with paper towells or a clean cloth to prevent airborne particles dropping in.
7. Put keg lid on. Attach gas line and add a little CO2. Your regulator should still be on its prior setting and this will be just enough to pressurise the keg a little and ensure the seals form.
8. Lay the keg on it's side with the gas inlet closest to the ground.
9. Check for leaks.
10. Now, increase the pressure to 30psi or 200 kpa (this is safe for all kegs known at present on this forum.) Leave the gas on and rock for 60 seconds. Turn gas off and then, (I've stolen this bit from The Ross Method of Forced Carbonation, a term that Ross gets annoyed about as it was not his original idea - lol!)
Turn off gas (on main bottle) but continue to rock keg while monitoring the pressure dial. You will see the pressure full back quite quickly & then stabilise (100 - 200kpa). The goal is for the pressure to fall back to between 140 - 160 kpa depending on your preference (140 pommie ale - 160 Aussie beer). If the pressure falls well below 140 kpa, just turn gas back on & rock for another 10 - 15 secs, then recheck & repeat as necessary.
11. When you have achieved the above, disconnect your gas line and fully unscrew your regulator valve.
12. If you want to drink straight away then very slowly purge the excess gas from the keg. Watch for foam coming out. If you can wait an hour or so then there will be less chance of foam! WHen the keg is fully purged, attach your gas line and then screw your regulator knob up slowly until you reach dispensing pressure - probably around 10psi.
13. Turn the tap on and have a beer.
So Shindiger, hope that helps. Lot of detail there so I'm really hoping you have cubes! If not, post back here and the process can be adjusted to your equipment. Also post back here if anything is unclear.
Cheers
PP
