Is it truly failure if you learn from the mistake?

In my last post, I laid out a potential recipe for my first attempt at root beer.  Later that evening, I made a 1-gallon test batch using an extract I got from Maryland Homebrew.

The recipe called for 1oz extract per gallon, which should've been 2 tbsp.  But I think they might've meant 1oz by weight, not volume because 2 tbsp was far too much.  Or, maybe they didn't expect me to add my own stuff.  In addition to the "basic" recipe (sugar, extract, and water), I added one vanilla bean (sliced, and scraped), and a tbsp of sarsaparilla root.  For sugar, I used 1 cup honey and 1 cup brown sugar.  It could've used at least another 1/2 cup.

  I let the vanilla and sarsaparilla simmer for about 30 mins or so, added the sugar, stirred until it melted, then added the extract.  Meanwhile, I had let the yeast wake itself up a bit in a cup of warm water and about a tablespoon of honey.  I used some "Fromunda" dry ale yeast from an older Mr. Beer kit.  While I put in the amount the extract suggested, the yeast was a little old, and I probably should've increased that, too, but I didn't want to risk over-carbonation and exploding bottles.

The end result was a sweet and somewhat tasty drink, but a little off.  I figured it was probably because it was warm, and needed a few days.

It's been a week.  I let the bottles sit out at room temperature for 4 days, then in the fridge the rest of the time.  While there's a bit of a refreshing flavor, it's obvious there's too much extract, and it just tastes like.... crappy root beer.  Even worse, while there is a refreshing *hisssss* when I open the bottle, there's almost no fizz, and practically zero head, which is essential to any root beer.  This means either not enough yeast, or not enough sugar. The bottles did firm up pretty good, so there was definitely some CO2 in there, but maybe because I used dry ale yeast (and old shit at that), it just took longer to build up CO2; next time I'll use normal bread yeast, which ferments faster.

There were somethings that went well: the honey was an excellent choice as it made the root beer significantly creamier tasting.  The sarsaparilla root was also kind of fun.  Can't really taste the vanilla though.

Next time, I'll half the extract, double the vanilla, and add a little extra brown sugar or honey.

It might also be better if I forgo the extract altogether.  I'd need to find a few extra roots, like wintergreen, cinnamon, and anise.