Sulfites and potassium sorbate when back-sweetening and fortifying

morunas

Hey everyone,
I've started with the following 20L must:
- 15L water
- 7 kg honey
- OG 1.112
- 5g of dry portwine yeast (Kitzinger Reinhefe, Portwein)
- yeast nutrient q.b. (no step feeding)
After 4 weeks low temp. primary (~16C), SG was read at 1.002, ~15-16% ABV, then racked and already flavored with a bit of smoked black tea and chocolate mint. Curiously, it tastes semi-sweet though at 1.002 SG.
I want to backsweeten with just a bit more honey to around FG of 1.007 and fortify up to 17% with 0.8L of 42% ABV brandy.
The yeast package only stated "high alc. tolerance" but online I found some saying tolerance 12-15%.
I absolutely do not want to restart fermentation or go bubbly, and I want to bottle using normal wine bottles (not pressure sustaining).
So, given that, should I add the sulfites plus potassium sorbate duo?
Cheers!

Miraculix

I would let it sit for one or two more weeks and take a reading again. If it's still 1.02, there shouldn't be any reason for the yeast to restart fermentation if you add more sugar. If you add more alcohol, there's even less chance of restarting fermentation.
Why are you fortifying it?

MightyMosin

My general stance is to always use the K-Meta... The K-Sorbate is up to you but I generally consider it mandatory if I'm going to use any fermentable sugar while back sweetening.