Denny is correct. I know that taste quite well---if you (as I often do) decide to taste the trub after your rack from primary (just stick your finger in like peanut butter!), then you surely know it. Or else, just drink the last 1/4" of beer out of your homebrew bottles. There you go. It's bready, like rising bread dough. Not entirely unpleasant, but I wouldn't want it in all my brews.
A few things to help alleviate this:
- Use a yeast with good flocculation
- When you rack to secondary, use a redirection cap on the end of your racking cane, so it doesn't rack much of the trub/yeast.
- Be patient: give your beer more time in secondary (2-3 weeks, or more for higher-gravity brews), and more time in bottle (at least 3 weeks for normal ales)
- When you're bringing your bottles from your storage to your fridge, be careful not to jostle them around too much, as it will stir up any yeasts that might have settled at the bottom of the bottle.
- When pouring the beer into a glass, carefully watch the color of the liquid as it pours out. As soon as it starts to turn lighter/cloudier, stop pouring. Sure, you might lose an ounce of beer, but it's all yeast. Also, if you're drinking alot, after you pour your beer into your glass, take a swig of the rest of the stuff (you know, that yeasty ounce in the bottom of the bottle). The vitamins will help stave off a bad hangover the next day.
Honestly, out of all those options, I believe the ones that help the most are being patient in secondary and in bottle. When I try beers very young, they're almost always a little yeasty, but that usually dissipates after a few weeks of bottle conditioning.