Well, I did it. Tapped 12 trees for the 1st time and collected 7G of sap so far. After researching using maple sap in a mash, I decided to go for it. Not expecting a lot of maple flavor, but if the trees keep running, I’ll also have some syrup to use at bottling time.
Started with the NB Caribou Slobber extract kit(this is one that I prefer the extract to the AG version). Added 1 lb. of munich malt, 1lb. maris otter, 2oz. more chocolate malt, 4oz. cherrywood smoke malt(that stuff is fantastic!), and 2oz. C120, to make it a PM batch.
I figured that the sap had a similar mineral content as my well water, which I realize is a big assumption, but I added 2gm CaCl2 and 1gm CaSo4 as I would normally. The sap had an SG of 1.015. Used 2G in the mash, 2G in the sparge and another 4G topoff to make my usual BK volume of 7.0G. Boiled for 75 minutes to get down to 6G. Because of the sugar in the sap and the extra malt in the mash, I used 5 lb. of the LME and 8oz. of the DME that comes with the kit. OG=1.060, which was my target OG. Pitched 1 rehydrated packet of US-05.
We’ll see, eh? 
I’m boiling my sap today. This year I’m not using it in my beer. I’ve tried adding my syrup to the boil in a couple beers and never got any maple flavor. This year the gravity of my sap is way low. What did you get?
1.015.
We had a couple of warm, rainy days last week and the sap ran well. Cold snap now, so it didn’t run this weekend, but we are supposed to have several warm days this week. I’ll probably have enough to boil down a batch next weekend.
I had .012 which is low for what I’ve gotten from my maples the last couple years. I boiled 40:1 this year. The last couple years I boiled 30:1. Must have been this crazy weather we’ve had in CT. I think the saps been running all winter and pulled out all the sugar. Generally I only boil first runnings since I don’t make a lot . I know the later in the season the sugar content goes down.
After a week of cold crashing and hitting it with gelatin(my standard protocol) I bottled today with 5oz. of syrup. I can’t pick up any maple character in the leftover sample post-bottling. CS is one that I know takes quite a while to come into it’s own, so I’ll probably post tasting results in 6 weeks or so.
4 week results: Beautiful clear brown ale, carbonated well with a nice off-white head that lasts. No maple flavor. And because the 8G of sap had an SG of 1.015, I figured(now) that this was like adding 2 cups(1/2lb) of sugar. Dried it out which made it more bitter tasting than the usual CS. I actually added 1cc of maple flavoring and 1/2 tsp. xylitol to a 12oz. glass which made it much better.
I’m going to give her more time to see if it’ll mellow out.
This is the part of homebrewing that can be frustrating. You can’t tweak a recipe unless you wait a month or six months or even a year…
As the Caribou Slobber base usually does, this has become better and better as time goes by. No maple character though…
I think next year I’ll boil down the sap to make syrup. THAT has plenty of flavor. 
Use the nasty, dark, late season sap that’s starting to lose its sweetness. Works great for beer! It leaves more of a woody flavor, but if you’re looking for maple character, that might be the best way to get it.
