I have five gallons of mead that went from 1090 to 995. The mead tastes good but way too dry, so I want to backsweeten it.
1. How much potassium sorbate should I add?
Instructions are usually quoted on the pack at X amount per gallon
2. I couldn't find sulfite, but my LHBS has potassium meta bisulfite - is that the same as sulfite?
Yes. I depends where you are, because over here the LHBS tend to stock Sodium metabisulphite, whereas in the US the common substance is the Potassium metabisulphite (also seems that it's the sulphite of choice for commercial winemakers as well, but it's more expensive here....)
3. How much honey should I add to get my mead to 1010 or 1015?
Added to taste, or to a specific gravity. I'd mix it 50/50 with water, then start with about 1/2 lb - take a gravity reading, and then a little taste. That way you know roughly what the level of sweetness you like is likely to be - and don't panic if the mead gets another haze when you've back sweetened as that can be removed either with more ageing or with finings.
4. What is the process? Do I put the sorbate and sulfite in before the honey? If so how long should I wait to add the honey?
This is my first mead, that's why I have so many questions.
That's exactly how it's done. The idea being to prevent any yeast cells still present from starting to re-ferment any additional sugars that are added (which is rather dependant on what yeast was originally used of course). So you'd add the sulphite and sorbate, make sure that it's stirred in nice and gently so as not to add much, in any, in the way of oxygen/air. Then you can either start adding the honey to back sweeten.
If you're intending to try and carbonate a batch, then you'd need to bottle prime i.e. add some priming sugar or honey directly into the bottle, but you'd have to make sure that you use champagne/sparkling wine bottles, stoppers and wire cages, to prevent making "bottle bombs".....
Hope that helps some....
regards
fatbloke