My Root Beer Woes ....

So I've been through a few batches of Root Beer using various supplied root beer extracts. Each time the root beer comes out feeling very YEASTY or "Brew-like" as opposed to the kick / bite of wintergreen and other flavours that I would anticipate.

My general recipe has evolved into the latest of my failed personal endeavours to
1 bottle of root beer extract (or a bottle and a half)
15 L of warmish water
1 point something pounds of white sugar
1 point something pounds of brown sugar
1 package of LALVIN 1118 champagne yeast (tried wine yeast and varying amounts)

Mix this all up and bottle it in PETN bottles. Let it chill and then drink.

Meanwhile my buddy who follows nearly the same process and same extracts (maybe different supplier) ends up with a completely different flavour.

My overall question is .... Is it my yeast or am i missing something in my process that could help me get the flavour I am looking for? Aside from brewing my own what can I do?

Do you not let it sit and carbonate for a few days before you chill it? It is also possible that the temperature that you two are allowing the yeast to carbonate the soda is not the same.

So the time it takes to reach the pre-cooling fermentation stage has alot to do with flavor? I typically take 4-5 days before my bottles are hard and then put them in the fridge. Could that be a problem; the length of time has allowed more yeast to grow causing the more brew like flavour?

I havnt tried sodas yet, but doing research and talking to the local brewers about my beers temp & time for the yeast are VERY important... ive noticed in the yeast reviews that the same strain of yeast will give, for example, floral tones at low temp & fruity flavor at higher temps... my guess is you are cooler temp than your bud causing a slower ferm (4-5days)... ive had one of my 5gal beers basically finish fermenting in 5 days...