You may or may not be familiar with the following information but I will run it all down for you.
1.You had what seems like the correct temp for this strain as a lower temp is not advised.
2.You pitched from what I gathered to be a “correct” yeast starter (IE: w/o stir plate and shook at least initially real well to oxygenate boiled-cooled starter wort /Or injected with O2 1 recently dated wyeast pouch would call for a 2L starter for an OG: 1.069 and optimally shook every couple of hours etc… you would end up with 250 billions cells created from 80-100 b)
Great, at this point you fermented the beer to completion and in the process the yeast create ethanol along with a host of other “byproducts” of the ferment as listed: (NOTE- the levels included are for white labs WLP028 which is same/ similar to Wyeast 1728)
Flavor compounds:
Esters:
Ethyl Acetate: Fruity with solvent undertones when above the flavor threshold. Considered an off flavor in beer when in high concentrations. (Detection Limits=10-100mg/l, Typical Level in Beer=10-50mg/l, Flavor Threshold=30-50mg/l, Tested levels=26.45ppm basically equal to mg/l will shorthand the rest.)
Isoamyl Acetate: Can produce banana and pear-like flavors when above the flavor threshold.
(DT=1-10mg/l, TLIB=0.5-3.0mg/l, FT=1-2mg/l, TL=0.24ppm)
Fusel Alcohols:
n-Propanol: Because the typical level in beer is below the flavor threshold, this compound generally does not affect flavor.
(DT=1-1000mg/l, TLIB=3-16mg/l, FT=600-800mg/l, TL=35.09ppm)
Isoamyl Alcohol: Can produce wine-like or solvent-like flavors when over the flavor threshold.
(DT=10-100mg/l, TLIB=50, FT=70mg/l, TL=129.83ppm)
Others:
Diacetyl: Butter like aroma at moderate to high levels.
(DT=0.05-0.80mg/l, TLIB=0.01-0.60mg/l, FT=0.08mg/l, TL=32.33ppb=.003233mg/l)
2,3-Pentanedione: Produces honey like aroma at higher levels.
DT= Approx 0.1mg/l, TLIB= N/A, FT= N/A, TL=6.32ppb=.00632mg/l)
Acetaldehyde: Grassy odors, bruised apples, cidery notes. Immediate precursor to ethanol.
(DT=10mg/l Lagers and 25mg/l ales TLIB=N/A, FT= N/A, TL=9.88ppm)
1.0 mg/l = 1.001 ppm 1.0 mg/l = 1.0ppb/1000
When the ferment ends the yeast now also cleanup some of these compounds so levels after week 1-2 will be greatly reduced if left in contact with a good portion of the yeast for a period of time usually 1-4 weeks depending on many factors sometimes months as is the case with lagers such as bocks, Marzen etc…as you then add other compounds such as SO2 depending on lager yeast strain.
You have hints of what is typically symptomatic of Acetaldehyde which typically “ages” or “conditions” out as a function as described above. This is one large reason in which you should not rush a ferment into the serving vessel until flavor trials indicate the beer is ready to consume and at it prime. (IE: no young characters.)
Ok, so that is the full story. I will though go on to mention one other thing that needs mention regarding fusel or higher alcohols usually the rate of fusels depends on temp, pitch count, oxygen or the lack of the following three but here is one other thing----- I made a good number of Sam Smiths Winter Warmer clones for a number of years that came out fine although a slight too much percentage of fusels in some of the ferments and the one thing I finally understood is that at any OG/ Recipe over 1.065 I typically now use a percentage of Sugar, Invert, Candi sugars etc… the reason why is you have far too many amino acids and FAN so the yeast are basically forced to create the higher alcohols. Whereas by using the sugar in percentage you cut the amino acids and FAN down so they are not forced into hyper drive. I’am obviously glossing over this quite a bit, but it was an AHHA moment when I read this about British and Belgian brewers using this practice to create BIG OG beers but with low fusels and in the end you get a more rounded brew. I tend to ramble sometimes. But I hope this was just good follow up info in the same vein of topics.
