It’s a great hobby. We started with 10 trees in the yard and now have 225 tapped. For finishing without a hydrometer ($15.00 very good investment), when sap is getting close to being done it will boil up and look like a head of beer. When this happens, remove from heat so it doesn’t boil over. Test syrup now for taste and thickness. If you want it sweeter and thicker, boil again till head comes up one or two more times. During this stage you must watch very closely (especially if you’re in the house) because if it boils over, your wife will kill you!