FAN levels, Berliner Weisse & yeast health

[drewseslu]

I am considering brewing Berliner Weisse. So far the plan mash so as to have a dextrinous wort, and conduct primary fermentation with normally with my light/amber hybrid yeast strain, then harvest this yeast for repitching. The Berliner then gets separated for secondary fermentations on brettanomyces and lactobacillius, then blended back together down the line for packaging.
The target ABV will probably be 4.1%-ish, with the primary fermentation contributing in the neighborhood of 3-3.5% ABV.
I don't think the FAN levels would be low enough to be detrimental to yeast health since the OG will be in the proper range, even though the primary yeast won't 'complete' the fermentation, and that I am probably over thinking this, but I wanted to throw it out there.

[william.heinric]

Infecting the Mash

One method that I like is infecting the wort in the kettle, allowing it to sour to the necessary levels, and then pasteurizing it in the kettle before fermentation. I know that has very little to do with your question, but I thought that I'd throw it out there. That method not only isolates the funky stuff to the brewhouse, but it also cooks off a large portion of the diacetyl.

In terms of FAN levels, if you are using a high portion of malted wheat and plan to oversparge the grain a bit, then I would think that you're going to hit your necessary nitrogen levels. Somewhere in DeClerk there's a note on the amount of soluble nitrogen extracted from different points in the sparge, with higher levels being extracted when less sugar is extracted. In terms of absolute levels, I think that it would be sufficient, but I guess that you're more concerned with FAN concentration.

Just remember that brewers have been doing this style for quite a while, and things have gone all right. More power to you for keeping it alive.

Cheers,
Bill