The Bavarian wheat should hold the banana taste, and as such I have brewed it a couple times as an open fermentation as it is said to enhance this tastes. But I would recommend you to just brew it by slightly under pitch the yeast, go low on oxygenation, and keep it cool at around 18-20`C. All this do promote the production of amyl acetate wich a Bavarian Hefewiezen should hold, and increase you like more banana tastes go semi open by letting the lid lay loosely on fermenting vessel. Then perhaps go full in and brew it open someday, but consider not to do this in the autumn as it is fruit flies season. Myself I attached the lid partly by pressing it on on one side of the bucket and hence loosely attached on the other side. Thereby the air can get in, but keep flies out. If you what to read a bit more into this see Stilportrait Weissbier (in German AND UK) and Fermenting with German Wheat Yeast! As you can see below I have tried verious version and I list the one I find best:
|Pilsner Malt||3||EBC||800||g||34 %|
|Wheat Malt||4||EBC||900||g||39 %|
|Flaked Wheat||3||EBC||250||g||11 %|
|Munich Malt||20||EBC||200||g||9 %|
|Cara Pils||4||EBC||100||g||4 %|
|Cara Crystal||120||EBC||70||g||3 %|
BIAB – 13,5 Liter water at 63-64@70 min in oven at 65`C / Mash-out 74-75@10 min on stove.
BIAB – 55@20min by 9,5 liter at 60´C resulting in the 55`C and then placed in oven@55`C –> Raised to 64-65@60min by adding 4 liter 80`C water again placed in oven@65´C –> Mash-out 74 grader over 15 min by raising temperature on stove.
|Lactic acid 80%||5.00||g||in mash water!|
|Fermentation||2g Danstar Munich CLASSIC Wheat Beer + 2g MJ M20 Bavarian Wheat||20||°C||12||days|
Regarding the yeasts. Then Mangrove Jack and the Munich Classic Wheat at low temperature and with lid open + just a bit underpitched gives a good banana tastes, but the Munich Classic Wheat have a high fluctuation and hence yeast goes to the bottom om the bottle and M20 yeast is better suspended. I tried combined these 2 yeast and ½ +½ goes very well in hand. The Munich Classic Wheat can be used to make an almost lager-like wheat beer if the bottle is poured carefully. Next time I wil raise the amount of wheat and leave out Cara Crystal!
http://beercalc.org/?t=140250 (Sourer Banana –> was infected I guess by fruit flies) .