First Batch, I think I messed up!

Was this an extract kit, or all grain? Did you do a full boil, or did you top off with water at the end of the boil? Did you take an original gravity reading? If so, is it off from the recipe's estimated gravity?

I'm guessing it was an extract kit which called you for to top off with water after the boil, and maybe you forgot to. In which case, you probably made a beer that is significantly stronger than what the recipe intended. Probably not the end of the world though...

 

Half the time, I get a few bottles less because of trub... totally agreed with od_sf, not the end of the world - let it carb then crack one open

What sort of beer were you making?

 

RDWHAHB (Relax, Don't Worry, Have a Homebrew). If your first batch is drinkable, consider it a success. So now you've learned a key lesson: know where 5 gallons comes to on your carboy. There will plenty more lessons to come. Enjoy!

 

The only thing I would be worried about is how much priming sugar did you use? If the kit told you to use a 5oz bag like most do you might have over carbonated.

 

good ol' carb-bomb...

 

I agree with the priming sugar concern..... If you added the amount for 5 gallons you may have some geysers upon opening.

 

Let's say the sugar added would have been enough to reach 2.5 volumes of CO2 in 5 gallons of beer, which is toward the high end of typical. That's going to translate to about 2.9 volumes in 4 gallons. That's not going to make geysers. Or let's say is was the dreaded (and misguided) 'universal 5 oz bag of corn sugar.' Into 4 gallons with residual CO2 from 70F, that's going to make abot 3.1 volumes. Again, not geysers. All bets are off if the sugar was not evenly distributed.

OP: How much sugar did you use?

 

Okay, so you were a gallon short of the 5, meaning you really had 4 gallons, right? Assuming table sugar, 5/8 cup would be about 4.4 ounces by weight. Which would get you about 3 volumes of CO2. That's high for most styles, but isn't going to cause gushing. If this was corn sugar, I can't even guess the weight. Estimates for conversion are all over the place because corn sugar is so compressible. It's always better to measure dry ingredients by weight.

 

The primary issue has already been addressed by vikeman. Otherwise, your ABV may be off, and it might be a little darker or some other aspects be a little different, but I have a sneaky feeling the world will continue turning anyway. If your process was sound, you'll still have beer, albeit a slightly different one than you planned. Brewing something that comes out different than you planned is usually not a disaster, and frequently it comes out quite tasty, and the rest of the time, at least drinkable. Don't panic.

If you are worried about bottle bombs, put your beers in a sealed plastic container while they carbonate. I would do this, not because I would be super panicked, but because the small chance of an exploding beer means a small chance of cleaning up a very large mess.