"Recipe author (Weikert) suggested 30 IBU's of Hersbruker at 20 minutes." "Brewersfriend" hops database said Hersbruker has 4% AA. The sample I bought was 1.8%. https://www.hopflavourblog.com/en/berechnung-der-hopfen-aromagabe/ has a great discussion of aroma hop additions and calculations. This article suggests 500 g/hL up to 700 g/hL. I opted to go 700g/hL (7 g/L x 21 L x 1 oz / 28 g = 5.25 oz rounded up to 6 oz). With the Styrian Golding, IBU's were only 22. Elected to add 0.25 g Nugget at 75 minutes for about 10 IBU's. So: 0.25 oz Nugget @ 75 + 6 oz Hersbruker (1.8% AA) @ 20 min + 0.5 oz Styrian @ flameout for 30 minutes gives about 32 total IBU.
1.7 qt/lb based on 14.25 lb of GRAIN (not incl. syrup) = 6.1 gallons of strike water. Heat HLT to 159 degrees, allow for 2 degree drop and shoot for post-dough-in temp of 148. add 1-2 gallons of cold tap water to drop remaining liquid in HLT to about 152.
Let mash stand 10 minutes before recirculating.
Mash at 148 for 90 minutes plus mashout at 170 for 20 minutes. Sparge for thirty minutes.
Add candi syrup with 20 minutes remaining in boil.
Start fermentation at 65 degrees and maintain for 75% of attenuation (estimate 84%). Raise to 68, then 70, then 72 as fermentation progresses.