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Other Fermentables / Re: Pressing apples and yeast selection
« on: September 27, 2010, 03:41:11 PM »
Don't expect to get the classic flavor profile from the hefeweizen yeast. The clove phenolics from the yeast depend on ferulic acid in the fermenter, and apples typically have a lot less ferulic acid than wheat and barley. Sources I found say that the apple crops they tested had 0.55 ppm ferulic acid. If it was 100% converted into 4-vinyl guaiacol then it should be above the flavor threshold (reported to be 0.3 ppm), but wheat beers are often have level of 4-VG 10 times higher than that and the enzymes that do the conversion don't work that efficiently apparently, so you're not likely to hit 0.55 ppm of 4-VG.
The isoamyl acetate comes more from pitching rate IIRC, so you should still be able to get that fine.
I'm not saying don't do it, I really want you to and report back how it goes! I'm just trying to give you an idea of what you can expect as a result.
Sources:
http://pubs.acs.org/doi/abs/10.1021/jf0346556
http://pubs.acs.org/doi/abs/10.1021/jf051717e
http://www.ncbi.nlm.nih.gov/pubmed/8590660
The isoamyl acetate comes more from pitching rate IIRC, so you should still be able to get that fine.
I'm not saying don't do it, I really want you to and report back how it goes! I'm just trying to give you an idea of what you can expect as a result.
Sources:
http://pubs.acs.org/doi/abs/10.1021/jf0346556
http://pubs.acs.org/doi/abs/10.1021/jf051717e
http://www.ncbi.nlm.nih.gov/pubmed/8590660



