It works. I carbonate a bottle of water in my sodastream add the chalk. It really only takes minutes for the amount I needed to dissolve for my Guinness clone.
You can do an iodine test. Take a few drops of your mash and add iodine. If it turns purple there is still unconverted starch.
Light malted barley should have enough enzymes to convert itself and quite a bit more other grains.
Pectic enzyme works better before there is alcohol present but add it anyway. It help clearing. Pectic enzymes won’t affect natural carbonation but natural carbonation and back sweetening don’t really go together. Makes bottles explode.
What article are you referring too?
I’m not sure about the foam but white particles might be crystals forming. Possibly potassium. You could try cold stabilizing.
But are you sure it’s done fermenting? What’s the SG?
Can you post a picture?
If he adds sulfite and sorbate he wont be able to carbonate it.
Let it finish fermenting before bottling. SG 0.990 or so. Add the appropriate amount of sugar for the carbonation level you desire and bottle. You won’t be able to have it sweet in the bottle and bottle carbonate it unless you use...