PH is something we learned to do very early on so that we KNEW what we were working with. PH plays such a big role in flavor on fruit wines and some cold weather grapes we work with.
No, it's not too late to take a PH reading. We use a meter because it's much more definitive---PH paper is just TOO ballpark. I would think that a pineapple wine should have SOME tartness to it--do you agree? If so, maybe a PH of 3.2 would be excellent. If it's too tart, it will take a lot of backsweetening to balance the acid. If it's not tart enough, it will taste very flabby. Like I said--I never made pineapple--but my instinct is to set the PH at 3.2
The reason calcium carbonate is used pre-ferment is because it takes it quite a bit of time to fall out--like 3 months--so that you don't have any chalky film or taste. Potassium carbonate is not a good choice for aromatic wines because it damages the aromatic profile--even a tiny amount of it. Calcium carbonate works best on cold musts, but since you are only using it to move PH and not to drop out tartaric acids, you can go ahead and dose the must now if you need to.
Check your PH--if it's around 3.2, I would say you're good. Don't over-do the calcium. If you do a search, you can find a calculations table for how much calcium carbonate it takes to move a PH a certain amount. I have to confess that we don't do it that way because we have so much experience using it for the fruits and grapes we work with.
Fermentation can sometimes look sort of slow, and yet be just fine. Some cultures are big foamers--many others are pretty quiet. Good luck--hope it turns out to be a good wine.
Another tip on PH---it's a wise thing to get a good dose of pectic enzyme into the must on the first day in order to start fruit breakdown. Also add some meta to protect it for that first 24 hours of allowing the pectic to work. The reason for this is the PH reading will be more accurate because you'll have some of the fruit broken down and incorporated into your juice sample that you're testing. The second day is always the day of testing, adding sugar to set brix, etc. More work at the primary is a good to learn as a new winemaker. The primary is where you're designing the wine--do a good job here and you won't have to do acrobatics at bottling to try to fix wine flaws. Good techniques will give you good results and you won't get disgusted with a hobby that just never seems to yield good results.
Pectic enzyme will help in clarification too--especially on pulpy, hard to clear wines. Doubling the amount can work wonders for those types of wines.
