Our group’s project was to compare and contrast
Chardonnay with and without Malolactic fermentation.
Chardonnay grapes are grown in many different
wine regions, but they originated from Northern
France. Chardonnay berries are small and are
light green to yellow when ripe. The berry
flavors tend to be quite neutral meaning that
we would expect our vinification techniques
to have a large impact on the final wine.
Some characteristics of Chardonnay include
apple, citrus, white fruit, and spice.
We did 4 grape analyses of Chardonnay from
September 5th to October 6th that evaluated
the grapes and measured the brix, pH value
and titratable acidity of the grape juice.
The results displayed an increasing trend
in brix of the grape juice as shown in this
graph. The pH values of the first three evaluations
were very consistent, around 3.1, while the
last one went up to 3.24. However, the titrable
acidity was not very consistent, ranging from
9-13.5 g/L. Throughout the process, the pulp
went from slightly hard and a bit tart to
very sweet, and the seeds color changed from
green to brown.
We started by sorting our grapes because some
of them had rot. Then we used the destem and
crusher to break open our grapes and remove
the stems. We then moved into pressing quickly
to reduce the contact time with the skins.
We used the basket press which is not the
most efficient. It took several pass
throughs in order to fully extract the juice.
After pressing we left the juice to settle
at 4 degrees celsius to remove sediment and
anything that made it through the press before
fermentation.
Our initial brix concentration was 22 degrees
which equates to about 13% alcohol. We decided
to use the QA 23 yeast strain because it produces
fruit aromas and is compatible with MLF. It
is a relatively fast fermentor and has low
nitrogen needs. In order to inhibit any unwanted
microbial growth, we added 50 ppm of SO2 in
the non-MLF fermentation and MBR 31 malolactic
bacteria in the MLF fermentation. We set our
tanks to ferment at 16 degrees C. Although
we did a sample for YAN, the results did not
come in time for when ⅓ of the sugar was
depleted. Therefore we just added ¼ of a
gram per liter of juice of FermAid K. The
fermentation took approximately a week and
a half to come to completion.
Both the MLF wine and the non-MLF wine presented
many bubbles during the first several days,
then the bubbles disappeared when fermentation
slowed. The results have shown that the brix
of the MLF and non-MLF juice decreased at
similar rates that went down from 22 on the
first day to around 0 in 12
days.
We used the Lavin MBR 31 bacteria for malolactic
fermentation and we co-inoculated with our
yeast. The bacteria addition is known to increase
the buttery flavor of a wine as well as increase
the body without diminishing the fruit flavors.
Malolactic bacteria consume malic acid, characterized
as a harsh acid, and turn it into lactic acid,
which is a softer acid, and releases carbon
dioxide.   As you can see during the process
of MLF the malic acid content of our wine
decreased. The initial concentration is after
fermentation and then points are shown until
the completion of MLF.
The biggest difference that our team found
between the two wines was in the mouthfeel,
the MLF wine has a much rounder mouthfeel
because of the decrease in malic acid.
Cheers
 
