This week I'm brewing the White Lightning Recipe in Zymurgy pg 20 and had a few questions.
For all grail it's 5# of grain, and then Muscat Grape Juice (4#) added after primary fermentation.
For extract, it's 1# of grain and 3.2# of DME. Muscat Grape Juice is added to secondary.
I will be doing the extract version with wyeast witbier.
First, why the difference in the grape juice addition? You have less trub with extract and it seems like it could be added to primary as well.
Second, it seems odd to add 4# of fermentable sugar after primary. Won't this force the active yeast to go through another fermentation? With less vitamins and oxygen they'll be stressed and produce off flavors. It seems better to add the juice 2-3 days into fermentation when most of my yeasts are still active.