Why is my FG off?

[Houdini]

Background: I just bottled my second batch. First batch I forgot to take gravity readings and the batch (True Brew Amber Ale) still tastes watery after 1.5 weeks in primary and 3 weeks bottled. However, I was having major issues getting my range to properly boil my water, among other mistakes, so maybe this batch just isn't going to turn out. I'm going to give it more time just to see if the taste improves.

Anyways, for my second batch (True Brew Nut Brown Ale) I used a turkey fryer and made sure to take gravity readings. As far as I can tell, I followed all instructions perfectly (other than being slightly late in adding my hops to the boil). My original OG reading was dead on at 1.050 (right in the middle of the OG range). However, after 16 days in the primary (no bubbling for well over a week) I went to bottle and took my FG reading. It was 1.016, but the FG range should have been between 1.012 - 1.014. I bottled anyways.

So my questions are:
1) Would keeping it in the primary longer lowered the FG? It hadn't bubbled in over a week so I figured fermentation is complete, although to be fair I didn't take multiple gravity readings over a few days to be certain.
2) What problems could cause the FG to be off?
3) How can I expect this to affect my beer, other than slightly less APV?

Thanks again for everyone who responds. You guys make brewing much less of a mystery.

- Houdini

 

[phenry]

First off: airlocks aren't a sign of fermentation happening or not happening. Hydrometer readings are. If two readings come out the same a few days apart, then you know it's done fermenting in most likely cases.

Also, the FG numbers that come with your kit are just estimations. Yeast can't read, so they don't know what gravity they're supposed to finish at. In all honesty you probably won't even be able to tell the difference, especially considering there's a bunch of other things that can affect a beer's taste much more such as pitching rates, fermentation temps, and wort oxygenation.

 

[RobWalker]

you need to take gravity readings 3 days apart and them be constant for you to know it's fully finished, it's very important.

it could even just be a stirring issue - you got more leftover sugars in one test because the wort was still thicker. in this case, i hope you stirred before bottling best way is to transfer to a bottling bucket.

Room temp is a factor too. Test your hydrometer in water, which should come up at 1.000 (usually.) If it's off, then adjust your reading as neccessary.

but yeah, most likely - it just finished higher. it happens.

 

[wyzazz]

So my questions are:
1) Would keeping it in the primary longer lowered the FG? It hadn't bubbled in over a week so I figured fermentation is complete, although to be fair I didn't take multiple gravity readings over a few days to be certain. Maybe and Maybe not, it depends on how fermentable the extract that you used was and what condition the yeast was in.
2) What problems could cause the FG to be off? Your FG is n't "OFF" as you say. That piece of paper you got with your kit is only a guideline, not the holy grail. Your yeast (under ideal circumstances) will eat until there is no sugar left for them to consume and then stop. In this case at 1.016.
3) How can I expect this to affect my beer, other than slightly less APV? Your beer will be slightly more malty, but I doubt you would be able to tell the difference between 1.016 and 1.014.

RDWHAHB

 

[jetmac]

This is one of the reasons other brewers don't have a problem giving away their recipes.
No way 2 people can brew the same recipe and hit the same exact numbers and/or have their beers taste exactly the same.

Your process can affect the way a beer turns out.

Where you bought your yeast from can effect how they perform if stored/shipped/handled differently than the recipe creator.

How you handled the yeast, the viability of the yeast, how much beer you actually had in your carboy to ferment, the temperatures you fermented at and on and on.

All these little things can change how a beer turns out.

You'll notice the expected final gravity is a range. Because you just don't know how it's all gonna turn out.

Being .002 points off is nothing to sweat. Your beer and the beer of the original recipe creator may taste exactly the same. Yours may be better. Maybe it tastes a little better with slightly less alcohol.

 

[djfriesen]

Also, there is a slight risk of bottlebombs. If there was unfermented sugars when you bottled (namely, you hadn't definitively determined that fermentation was complete), and you primed on top of that, you might end up over carbing your bottles and boom! But then again, chances are a couple gravity points won't make any difference. Just something to think about.

 

[tryn2brew]

Personally I usually allow a minimum of three weeks before putting my beer into bottles. One week in a primary, and two in a secondary. You mention 16 days, so you might be a quick to bottle. I often go more than a month before bottling.