I make it, lots of work and subject to the whims of the weather makers but a good product if done correctly. A sugar maple tree can fill a 2 gal bucket a day in good weather. It should drop below freezing at night and above freezing in day, the wider the spread the more raw sap. I use -5c to +5c as the desirable range. Ratio of sap to syrup depends on tree but 40 gals of raw sap to finished gal of syrup is a norm. Finished syrup, for public sale in Ontario, must meet some published standards, (i.e. sugar content as measured on the brix scale) but home brew can be as you like it. Most mass production is done using tubes from trees to collection point, filtering using Reverse Osmosis, boiling using oil or gas fired boilers, steamed pre-bottling filters, etc. We do ours the old way, 300 pails, handraulic collection into a tub on a wagon,wood fired pans, etc. Sold about 100 liters last year.