I would bet that BrewBama is definitely on the right track. An example of how getting a beer dialed in is a matter of balancing lots of factors that individually aren't decisive, but all add up. Miss your pH, your mash time/temperature program, your pitch rate, don't account for the yeast's tendencies... no problem on any one. Get them all just a bit off, and the aggregate effects are noticeable. And you'll want to learn to consider them as a system: Think, which factors can I control, and what do I need to do to make up for my limitations? In this case, if you couldn't better manipulate time, temperature, and chemistry, you might choose a different yeast. If committed to the yeast, you'd probably pay more attention to the mash program. And so on.