I am brewing the Schwarzbier recipe from BCS. What differences will I notice if I sub Chocolate malt 350 (which I have on hand) instead of 420 (what the recipe calls for)?
340-350 is the sweet spot for chocolate flavor. 420 is roastier. If you want to try to mimic the 420, you maybe could use a combo of 350 chocolate and a pinch of roast barley, if you have that. I'm not sure how chocolatey you want a schwartzbier.