The Crush - August 2019 - 1

Volume 46 Issue 8 August 2019


Preparing for Grape Harvest

By Ted Rieger
Pre-harvest planning and preparations at California vineyard
operations are critical to ensure the best outcomes for harvest
timing, grape quality, grape delivery, equipment operation and
safe conditions for all harvest workers. The following is a brief
overview of recommendations and reminders to help harvest
personnel prepare for the 2019 grape harvest.
At a recent UC Davis seminar on harvest decisions, Cakebread
Cellars viticulturist Lise Asimont, who has extensive experience
in California vineyards, provided general observations about the
2019 growing season to consider for this year's harvest. Given
the high rainfall year and rains in late May, large vine canopies
and vigor are factors in many regions. Fungal issues, such as
powdery mildew, botrytis and other molds, could be concerns in
areas without adequate spray treatments or coverage. Asimont
advised looking within clusters for bunch rot.
Vines, rows or blocks with poor quality fruit can be clusterthinned ahead of harvest if labor is available, or flagged in
advance to inform workers not to harvest these vines. Harvest
season is also when vine leaves may turn red due to leafroll or
red blotch viruses. "Identify areas with possible viruses and flag
them to monitor spread," she said. "If you have fruit that can't
ripen, or won't ripen to quality standards, leave it in the field."
Asimont offered tips to evaluate grape ripeness for picking
decisions. In-field grape tasting, sampling and testing should be
oriented toward the wine goal, and the wine style, particularly
blocks intended for a specific lot or program. Field evaluation
includes color inspection and tasting for flavor. Skin
extraction can be indicated by chewing/
macerating in the mouth, then taking the
berry skin out of the mouth to examine
for color extraction. Seeds should be

Cal Ag Safety trainer Anthony Garcia (L) advises Lodi growers on mechanical
harvester safety. Photo: Ted Rieger

examined for degree of lignification/browning versus greenness.
Asimont recommends rachis tasting in red varieties as "it can be
representative of the degree of ripening."
Whether to use berry sampling versus cluster sampling can
vary by vintage and variety. If there is more variability in fruit
development and ripening, cluster sampling may be preferred.
Fruit sample collection should be varied and random (each side
of the vine) and avoid the first five vines at the row ends. For
berry sampling, Asimont advised five berries per cluster from
each part of the cluster.
Basic lab testing of fruit sample chemistry should include
Brix, titratable acidity (TA) and pH. Malic acid can provide an
indication of vine balance and health. She recommends phenolic
testing for reserve blocks "to gauge how much more to push
ripeness." Pyrazine testing may be done for problem blocks.


The Crush - August 2019

Table of Contents for the Digital Edition of The Crush - August 2019

The Crush - August 2019 - 1
The Crush - August 2019 - 2
The Crush - August 2019 - 3
The Crush - August 2019 - 4
The Crush - August 2019 - 5
The Crush - August 2019 - 6
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