Any Port in a Storm, Part 2

I've picked the last of the plums from the garden and I think I'll have enough to make a second batch of port (if Dr D doesn't snaffle them all for jam first. Not that I'd complain...)

The first batch is looking fantastic.

Mmmm yeah - show me your potential!

This is the must pre pitching the yeast: 13% potential alcohol by volume, given the sugar content.  Given that this is a port it will end up stronger as I pitch some brandy in to end the fermentation. 

I pitched the yeast and left the must with the lid on loosely for 24 hours, stirring the the plum mash every couple of hours or so. There was mighty fizz overnight!

I strained and siphoned into a 5l demijohn the next day. (Siphons! Yay!) There are some small flecks of fruit solids but nothing larger than a breadcrumb. I brought the SG up again: my hydrometer said the potential alcohol was 10.5% (w00t! 2.5% alcohol already! That's right, yeah? Experienced homebrewers, to my aid, please!) so I brought it back up to 13% with a strong sugar syrup. 

Gloop

Fizz

It's bubbling away very happily to itself. I measured the potential alcohol again - 10.5. That's another 2.5% alcohol I reckon...  This is all very approximate you understand :) 

So 5l of liquid at 5% by volume is 250ml.

With this yeast I should be able to get to 14% ABV easily (700ml). Add a litre of 36% abv brandy and I have 6l of 18% port... in theory... If I have the maths right...

I may have to sweeten again after that but I'm assured that that is a legitimate approach. If someone could clue me in as to whether I should do that or whether I should add more sugar before fermentation stops that'd be great!

Watch this space!