For The Love Of Port

Has a producer ever said when actually stop the fermentation process

I'm not understanding your question. Can you clarify it, please?

No problem Andy
In terms of hours , when is the spirit added in order to stop the yeast

I thought it's a week

Doesn't Graham add the grape spirit earlier than most

Oscar Quevedo has a video on you tube and he says he adds the brandy at the half way point
Would that imply that Graham's adds the brandy earlier

On average, it is around 3 days after the grapes are put in the lagares. Some producers are adding the arguadente at a different time base on residual sugar mostly. So if Graham's as you state wants to have a sweeter style they have to fortify earlier or harvest riper/sweeter grapes.

So would it be safe to say that on average there is no residual sugar remaining after three days

Luc Gauthier wrote:So would it be safe to say that on average there is no residual sugar remaining after three days

There is a lot, you want to keep sugar, this is why you kill the yeast, fermentation stops and natural sugar remains. Between 80 to 120 g/l depending on producers.