Excessive bottle carbonation - what am I doing wrong?

[TrevTheBev]

I'm relatively new to homebrewing [After an absence of 30+ years]. I've made 4 lots of different beers since February this year [All kits] and have had absolutely no problem with excessive [Or under] carbonation.
I'm using all 1 litre PET bottles that had Tonic/Soda water in them, completely sterilised and rinsed out. I don't rack the beers from primary vessel to secondary vessel but merely wait an extra few days once the FG reading is what it should be. Then, along with my [Invaluable] little bottler attached to my tap, I simply place 2 or 3 teaspoons of sugar into each bottle and give a good shake when they have all been filled. I have used carbonation drops in the past but find that sugar gives and keeps a better head for longer and is so much cheaper. I know there is always some sediment at the bottom of the bottles but I personally, find that the most straightforward method for my use.
Why over complicate things when the simple method works ??

 

[moto748]

I use the @Scottyburto method as it's consistent and works when I bottle condition.
Have to admit have now moved onto counter pressure bottling most of the time and that removes the mystery. But still use the liquid sugar and syringe if it's a big beer to " mature " in the bottle.

I use the syringe method too. I find it works well, and you can be confident of exactly how much sugar is in each bottle, and if necessary you can adjust slightly on the next brew.

 

[RoomWithABrew]

Putting sugar in liquid form ensures it gets mixed as the beer is siphoned in. No need to shake and expose the beer to the oxygen in the top of the bottle. Yes the yeast will use up the oxygen but it can't undo any oxygen that oxidised your beer before it had a chance to use it.
Oxygen is basically the enemy of all beer and a friend to yeast sometimes.
No real need to shake that sugar into solution if you want to continue to use it dry either, if you use a carbonation drop ( like a boiled sweet ) you don't have to shake the bottle to dissolve it after placement it gets there on it's own.