Step 5: Addendum: How to get really clear candies
I figured out how to get really clear candies with almost no bubbles.
I started by straining my vitamin C through a paper coffee filter so I got most of the solids out. I ended up with a very sour liquid that looked like water.
The secret to clear candies is to melt it twice.
After the first cycle of heating, let it rest, and cool off in the refrigerator. Almost all of the bubbles will rise to the surface while it is cooling. When it is cool enough to handle, take it out of the cup (the foam layer sticks to the cup, just cut through it around the edge of the cup with a knife). Put some water in the cup to get that foam to soften up so you can clean it out before you heat the candy again.
Now take your lump of clear candy with the foam layer and cut the foam layer off. I found a clean pair of kitchen scissors works well. I call them "kitchen scissors" because I only use them with food and they stay in the kitchen. You can use any kind of scissors. I cut the big piece into chunks, then I trim the foam layer off.
I've also done this with a knife but you have to be really careful. I don't worry about getting it perfect. The bit of clear that remains on the foam can be melted down at the end to make some candies for the cook to eat after the main batch. When you melt the foamy chunks, you will probably find the clear part melts into a very clear layer. You can siphon that out with your syringe if you want. I just pour it in to about spoon sized circles on a silicone baking mat. Then I peel those dots up when they solidify and put them in a baggy for me to eat. They taste just as good.
Melt all of those clear chunks. No real need to stir it while it is melting. I leave it alone so I don't add any bubbles. I just give it a gentle stir at the end before I suck it up into the syringe.
This technique makes amazingly clear candies. I have two pyrex cups so I make a second batch while the first one is cooling, then while No. 2 cools, I cut the foam layer off No.1 and melt it for casting.