That's an interesting read, but I'm not sure that it would represent results from an all barley high gravity wort most homebrewers would prepare. Do you think this could be Nitrogen limitation?
A 12°P wort requires 150mg of FAN per Liter which is 12.5mg per liter degree Plato.[1] It looks like there is a typo on Table 1 of the paper you linked. There is no way there is more FAN than Maltose unless it is supplemented, which is not shown in the Materials and Methods. FAN is normally measured as mg per liter, so it's probably safe to assume that's what they meant. It looks like the supplements did not contain a nitrogen source which would make this study not map well to a high gravity all barley wort. The FAN concentrations are very low compared to what is typical for beer.
FAN L-1 °P-1 should be about 12.5mg. Note that only the un-supplemented wort has more than 12.5mg L-1 °-1
Code:
°P FAN(mg) L-1 FAN(mg) L-1 °P-1
14 240 17.1
21 210 10.0
21 220 10.5
24 192 8.0
24 201 8.4
The growth rate of s. cerevisiae is about 1/8 of the rate under nitrogen starvation, and the biomass yield is about half.[2] This would explain the results that were shown with this study.
[1] O'Conner-Cox, E. S. C., and W. M. Ingledew. 1989. Wort nitrogenous sources. Their use by brewing yeasts: a review. J. Am. Soc. Brew. Chem. 47:102-108.
[2] Schulze, Ulrik, et al. "Physiological effects of nitrogen starvation in an anaerobic batch culture of Saccharomyces cerevisiae." Microbiology 142.8 (1996): 2299-2310.
![Craft A Brew - Safale S-04 Dry Yeast - Fermentis - English Ale Dry Yeast - For English and American Ales and Hard Apple Ciders - Ingredients for Home Brewing - Beer Making Supplies - [1 Pack]](https://m.media-amazon.com/images/I/41fVGNh6JfL._SL500_.jpg)
