newb sugar addition question

sorry if this is the wrong place or just a stupid question, but hey i'm a newb. the other day i brewed the AHS double IPA extract recipe. made a 1.1 liter starter with stir plate and pitched that in. the recipe says the OG should be 1.088. well while i was boiling, i think i got it too hot and burnt some of my sugar (weird hissing sound when i stopped stirring). i stirred as much as i could to keep from burning it all and lowered the temp, but (after the 1% boost of an extra lb of sugar) i still only ended up a 1.090 OG. well it has been in the fermenter for 6 days and has dropped to 1.020 and the FG is supposed to be 1.016. my question is this: i was hoping to get about 10% out of this with the extra sugar, but i think i burnt most of it in the boil. so, would it be okay to boil a little water and mix up about .5 lb or so of cane or brown sugar to throw in the fermenter? since the krausen has mostly settled, is it too late to add sugar? am i showing my ignorance for thinking of doing this?

No, it's not too late, but your DIPA probably isn't done fermenting yet. It will likely drop a little bit more in the next week. I would leave it alone.

But if you really want to, you could add sanitized sugar and hops. I have done this on a DIPA and it came out great.

how can i tell how much the 1lb. of extra sugar affects the ABV? can i just take a gravity reading before adding the sugar, add the sugar, then take a second comparison reading? then i could just add the difference to my OG?

i believe 1lb of corn sugar adds 1.035 points of gravity per gallon of wort. so 1lb in 5 gallons would raise the OG by 1.007

Sure I think you could do it, sometimes its even suggested to add your sugar to high gravity beers closer to the end of fermentation, but you've already added 1 lb of sugar, adding another 1lb might start contributing some cidery flavors. I bet you have a nice beer already. If it were me, I'd just leave it be. Good luck.

thanks. i did a few things that kinda threw this batch off a bit, but i'm learning. i appreciate the help.