SG for Port?

[UnderThePorchBrewing]

this might be a stupid question to ask now but hope somebody can help. I am making my first true port and will be fortifying it soon. are there any general guidelines for back sweetening the wine to a certain gravity either before or after fortifying it? or go by taste? or should I buy a port I like measure the SG and shoot for somewhere near it?
Ben

 

[Twerp129]

Taste is your best bet. Play around with bench trials. After all SG is a measure of gravity rather than sweetness.

 

[UnderThePorchBrewing]

thank you
this is what I thought but decided to check beofre the weekend when I commit myself. as a brewer before wine I was going to use corn sugar but I have also read that grape juice and grape juice concentrate can be used. any thoughts?
Ben

 

[Twerp129]

Port is traditionally not back sweetened, a neutral grape spirit is added when an acceptable level of residual sugar is left near the end of ferment. This fortification boosts the ABV to a level in which yeast cannot function. I think grape juice would give you a more natural feel than corn sugar, but I've only ever made Port style wines by introducing a neutral spirit and then blending barrels to achieve the desired sweetness and acid balance, so I'm not much help here.

 

[UnderThePorchBrewing]

I did not stop the wine in time and it fermented out so my only option is to back sweeten. per your advise will probably use a juice. next time will be more vigilent with when to fortify and stop it.

 

[Twerp129]

It happens, grape juice should work a treat. Plus it's easier to get your exact preference of RS this way.