Brewing with maple syrup

TroubleShooting

Mark Daspit • Tracy, California asks,

I recently brewed an old ale with an OG of 1.082 and an FG of 1.015. During the last 10 minutes of the boil, I added about 12 ounces (340 g) of maple syrup. The pre-fermentation sample to obtain the OG had a very nice maple aroma and flavor to it. I siphoned the beer into an aging vessel for some long-term storage and am now considering my options. Given the high alcohol content, I want to bottle it and drink it sparingly so that I can see how it matures over time. My intent is to have a low volume of carbonation, say on the order of 1.5 using maple syrup so that I can reintroduce that aroma and flavor. My understanding is that maple syrup is sucrose, and to obtain a CO2 volume of 1.5 in 5 gallons (19 L), it would require approximately 4 ounces (113 g). The final amount in the aging vessel is about 41⁄4 gallons (17 L). What adjustments do I need to make given that I am using maple syrup in liquid form? How should I be measuring this and what amount is appropriate for 41⁄4 gallons (17 L)?