Not hitting the FG on a beer I have made lots of times successfully.

[Tiger Ed]

I brewed a Bitter I call Old Rose Reserve. Its a beer I have developed and made successfully a good number of times. Everything went well I hit my OG of 1043 put it into the fermenter pitched the yeast (Danstar Nottingham Ale) that had been hydrated  before pitching. It went off like a rocket (Much more than normal) for the first 4 days then slowed for a further 2 days when fermentation had finished completely I left it 14 days and went to bottle it tonight. When taking the FG I found it to be 1020 it should be 1009. This is the 1st time this has happened. It tasted good so I have chosen to bottle it but I am now worried it will not carb up. What do you think and what do you think stopped it reaching its FG this beer has always been a great success right from day one.

[TheSumOfAllBeers]

There are a number of checks you can do (read: should have done) before packaging up the beer.

You dont know yet if the beer still has fermentables in it. It may be the case that you mashed something crazy, or added some all-dextrin malt instead of base malt, in which case your actual FG is what you measured and there is little you could do about it (but its safe to bottle).

It could also have been your yeast being tired, or a low viability packet. In which case you have a lot of fermentable sugar that your yeast got lazy about. This is likely to make for some bottle bombs, i would take a few of your bottles and place them inside a safe container in a warm location (high 20s) so that they will condition quickly. If they explode in the container, or gush dramatically on opening, then you have a problem with your other bottles, that you can only rectify by opening & degassing.

[DEMPSEY]

As above advice. Also are you getting any oxygen into the wort before you pitch the yeast. Post up your recipe and mashing process.

[Tiger Ed]

Thanks guys for your replies. The funny thing is this is a beer I have made many times, with no changes to the recipe and no changes in brewing procedure so you would think I would be walking a well worn path. I always aerate the wort by letting it drop slowly from a height out of the boiler in to the fermenter and then giving a prolonged stir before pitching the yeast. I hope you don't mind but I would prefer not to post the recipe as I hope to enter it in competition (Its that good) I will post it after I've been shot down in flames in my 1st ever competition.

[DEMPSEY]

Nah bother on the secret recipe . Do you keep lots of notes when you brew like gravity readings, PH readings along the way, full conversion of the mash. Notes are handy as weeks go by even months and trying to recall a brew day is challenging  enough.