When reading up on brewing Weissbier (also known as Bavarian Wheat) one of the suggestions is a ferulic acid rest. This rest around 43 C
(110 F) works best at a pH > 5.7 and liberates ferulic acid into the
wort. This ferulic acid is the precursor to 4-Vinyl-Guajakol which is
responsible for the the clove flavor produced by Weissbier yeats. The
more ferulic acid there is in the wort the more 4VG should be produced
by the yeast and the more clove character the beer should have.
This
is what I wanted to test. So I brewed a Weissbier recipe twice. Once
with a simple Hochkurz mash and another one with an additional 30 min
43C rest at a pH > 5.70. For the second beer acid malt was added at
61C. This is above the optimal range for protoelytic activitry since I
also wanted to limit the protein degradation during the time the mash
spent in the 45-55C range.
The following table lists the process steps taken for the 2 beers:
|
|
82 Weissbier IIIa |
83 Weissbier IIIb |
|
water |
70 ppm Ca, 4 ppm Mg, 10 ppm Na, 13 ppm SO4; 30 ppm Cl, 118 ppm RA = 43 ppm CaCO3 |
70 ppm Ca, 4 ppm Mg, 13 ppm Na, 13 ppm SO4, 15 ppm Cl, 138 ppm |
|
grist |
33.5 % Vienna Malt 64 % Pale Wheat Malt 1.5 % acid malt |
34 % Vienna Malt 64% Pale Wheat Malt 2 % acid malt (added at 61C) |
|
Mash |
63C for 30 min; pH 5.57 heating 1 C/min 71C for 40 min heating 1C/min 75C for 10 min |
43C for 30 min; pH 5.77 heating at 1 C/min 63C for 20 min; pH 5.54 heating 1 C/min 71C for 40 min heating 1C/min 75C for 10 min |
|
Hops |
0.52 g/l Hallertauer Tradition 6.8% for 60 min (added before |
0.52 g/l Hallertauer Tradition 6.8% for 60 min (added before |
|
Yeast |
WY 3068; 1000 ml Kraeusen |
WY 3068; 1000 ml Kraeusen |
|
primary |
7 days at 18.5 C |
6 days; started at 16C and was raised to 20C over the next 3 Lowered temp to 12C while WLP830 (W34/70) was prepared. While at 12C for 10 days the gravity fell from 5.7 to 3.6 Carbonated at 17C for 10 days |
|
maturation |
5 days at 10 C; 10 days at 17C for carbonation; |
see primary |
Note that the fermentation for the 2nd
batch slowed down signficantly after it reached a gravity of 6 Plato.
At this point I decided to pitch a lager yeast and I cooled the beer
for the time it took to propagate that yeast. This was to drop out most
of the original yeat and limit autolysis. This was unplanned and I hope
it is not the reason why the results of the experiment are like they
are.
Tonight I tasted the two beers:
|
|
82 Weissbier IIIa |
83 Weissbier IIIb |
|
age |
7 ½ weeks |
5 weeks |
|
aroma |
slight clove slight banana not much difference |
slight clove slight banana not much difference |
|
head retention |
fairly stable not much difference |
fairly stable not much difference |
|
appearance |
dark golden color |
dark golden color |
|
taste |
sweet start that finishes with a distinct clove note which not much difference between. The clove note seems to be at the same level. |
sweet start that finishes with a distinct clove note which otherwise not much difference The clove note seems to be at the same level. |
|
mouthfeel |
average mouthfeel (compare to standard German Pils) |
average mouthfeel (compare to standard German Pils) |
|
stats |
original extract: 11.75 Plato limit of attenuation: 77% actual attenuation: 77% apparent extract: 2.7 Plato pH: 4.25 |
original extract:12.7 Plato (I got better efficiency than expected) limit of attenuation: 78% actual attenuation:78% apparent extract: 2.8 Plato pH: 4.11 |
Conclusion: For the chosen yeast holding the ferulic acid rest
didn't make any noticeable difference in the clove flavor that was
produced during fermentation. While additional experiments should be
made to confirm these findings it is very much possible that this rest
is not worth the additional work.
(comments are disabled b/c
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