My first lager is in the house from my farm shop fridge, transferred to a clean carboy and warming up for priming and bottling this weekend. Right now, it tastes remarkably like Samuel Adams Boston Lager and has about the same IBU. I won't call it a clone, but it does taste a lot like it as of now.
As predicted by the more expert folks here
(thank you!), the fruitiness is gone now. Since it appears a success, here's the recipe.
AMERICAN MARZEN EXTRACT RECIPE (with conversions for all-grain)
6 gallon starting boil, yielded about 4 to 4 1/2 gallons to bottle for me.
In bag:
1.5 lb. Weyerman CaraRed
2 lb. Belgian Bisquit
Steep 30 minutes (All-grain: add to mash)
Remove from heat.
Add:
6 lb. Maris Otter LME (All-grain: Converts to ~ 8 pounds grain)
1 oz. Centennial hops (bittering)
Boil 45 minutes
Add:
1 lb. table sugar
4 oz maltodextrine (All-grain: Skip this addition)
1 oz. Centennial hops (aroma)
Boil 15 minutes.
Remove and cool. Once wort is cool to yeast pitching temp, transfer to fermenter and...
Add:
1 vial Clarity Ferm (Brewer's Clarity) - Optional. Clears & makes it low gluten.
Safale S-23 Lager Yeast (this is what I used, sprinkled on top; use your preferred yeast)
Ferment in a cool place or using a water bath or refrigeration to achieve 50-54 degrees liquid temperature.
When krausen falls and fermentation slows (it took me a week),
transfer to carboy or gallon jugs and refrigerate for lagering. (I simply stuck mine in the fridge in gallon jugs.)
Lager 4-8 weeks.
Prime and bottle (I'll use 1 oz. table sugar per gallon), or transfer to keg and carbonate.
Notes:
1. ABV: 5% (German Marzen typically 5.8-6.3%; Samuel Adams Boston Lager, 4.9%)
2. Calories per 12 ounce serving: 168
3. By German law, a Marzen can only be made October through April, when temperatures are favorable in Germany.