[Squirrel]

New to home brewing. Have tried the Mr Beer American Classic Lite(comparable to Bud Lite, Coors Lite etc..) 3 or 4 times, still getting slight aftertaste. Mr Beer recommend 1) allow wort to cool 1 hr before adding to keg 2) use a different brand of sanitizer 3) use a different brand of purified water. Still a slight aftertaste. After brewing, keg is kept in a dark closet for about 7-10 days at a constant 70-72 degrees; bottled in dark glass bottles and kept same as above for 3 weeks. The beer is not undrinkable but not what I'm after. Maybe some different refill kit suggestions, brewing/bottling ideas, not sure; like the home brewing just frustrated! Thanks in advance!   

[Frankenbrew]

Fermenting in a closet at 70-72 may be too high.

[majorvices]

There's no way you are going to be able to duplicate an American Lite Lager without good temp control and a good understanding of yeast and fermentation. For any lager, German, American, etc. you will need to ferment the beer in the 48-52 range with a true lager strain for at least 48-72 hours. You could make a great ale as well with the same recipe and use dry yeast but even then fermentation will need to be kept under control, low 60's high 50s.

I brew commercially and it is certainly not impossible to make a Lite American Lager but for beginners it is a fairly mighty challenge. Those beers have almost ZERO flavors to begin with, any fermentation mistake is going to show up very easily.

[dls5492]

There's no way you are going to be able to duplicate an American Lite Lager without good temp control and a good understanding of yeast and fermentation. For any lager, German, American, etc. you will need to ferment the beer in the 48-52 range with a true lager strain for at least 48-72 hours. You could make a great ale as well with the same recipe and use dry yeast but even then fermentation will need to be kept under control, low 60's high 50s.

I brew commercially and it is certainly not impossible to make a Lite American Lager but for beginners it is a fairly mighty challenge. Those beers have almost ZERO flavors to begin with, any fermentation mistake is going to show up very easily.

+1
I recommend that you take your beer to a local Homebrew Club. They can help you identify the aftertaste, how it got there and how to remedy it.
Welcome to the hobby. Learning is an exciting adventure!

[Slowbrew]

It is probably temp related but can you tell us what the aftertaste tastes like?  Metallic, cardboard or some other flavor?

As an example; I noticed a metallic aftertaste from my American wheat last night but only in the first glass.  My second was clean.  In my case it is either oxidized due to old age or I need to clean my beer lines (or both).  Different flavors mean different causes, usually.

We;come to the fun!

Paul

[Bilsch]

Besides Majorvices spot on advice, I'll bet that extract twang or old malt extract is a component of what your tasting.

[ethinson]

There's no way you are going to be able to duplicate an American Lite Lager without good temp control and a good understanding of yeast and fermentation. For any lager, German, American, etc. you will need to ferment the beer in the 48-52 range with a true lager strain for at least 48-72 hours. You could make a great ale as well with the same recipe and use dry yeast but even then fermentation will need to be kept under control, low 60's high 50s.

I brew commercially and it is certainly not impossible to make a Lite American Lager but for beginners it is a fairly mighty challenge. Those beers have almost ZERO flavors to begin with, any fermentation mistake is going to show up very easily.

The 70-72 is probably still too high, but just to clarify (since I started on this exact same recipe as well) the "American Lite Lager" from Mr Beer uses Ale yeast.  I assume the "lager" is the style they are trying to replicate (B/M/C type beers) but it's not an actual lager.  It was very confusing talking to people about it, especially early on when I didn't know as much as I know now. 

In theory, sanitizer shouldn't affect flavor, but what are you using? Bleach or iodine might leave a flavor if it was too strong.  I'd recommend something like StarSan that doesn't require rinsing.