Primary and Secondary fermenter?

Ok, so I've done two home brews that I've only used one fermenter. The very first two brews I did were excellent and came out great and I used a primary and secondary, but the third and fourth I did not. Both had the same distinct, strong, off flavor (not soured, but off) and I do not know the reason. Is it because I am not using a primary and secondary? Should I ALWAYS use two?

Thanks,
Inarus

If you do the same brews but use secondary then you can see if it makes a difference.

You don't always have to use a secondary but I suggest if you don't have the experience to know if you need to or not then you should.

I personally rarely use a secondary.

I have only experimented a few times with primary-only brewing. Right now, I wouldn't hesitate to do an extended primary (probably 3 weeks) with lighter gravity beers, hefeweizens, etc., but for anything with an OG above 1.055 or so, I'd probably secondary it.

Well the issue is I have a very odd taste in the beer. It's not a soured taste, but just off. A friend of mine who's dad did home brewing said that it tasted very strongly of hops in both cases. I'm not sure why this is occurring, but it has happened now in two sets of two different beers. My first two beers (which I did in a primary/secondary setup) tasted just fine, but these who that were not done that way taste way off.

Extract Twang??

I'm not sure what that tastes like, but it might be a possibility. Although I've gotten my 2nd, 3rd, and 4th batches from the same place, only the last two had this flavor. The first one from that store was fine, and it had the same Amber extract.

This thought just occurred to me.

In the last two batches I did, my sanitizing was a little hasty. Perhaps some of the bleach from cleaning got into the wort and caused an off flavor? if this was the case, what would it taste like? Would the beer ferment? It was definitely fermenting, but both times it had an off flavor. I'm usually very good about sanitizing and then rinsing with clean water, but could this be the case?