VASCM: Harvest Advice Please

Sun Oct 24 21:23:54 GMT 2021

Rain during harvest is very common in Germany so I’m familiar with the
struggle.
Besides the mere nuisance of picking while the ground and the grapes are
wet, there are a couple of things to consider.
If your brix are low both the water the vine takes up from the ground and
the water sticking to the grapes can lower your sugar concentration
further. Either pick before the rain, plan for additional hang time after
the rain, or consider a lighter wine style.
The water from a short shower can be blown off with a leaf blower or an air
blast sprayer.
The sudden influx of water - and with it nitrogen - can make grapes prone
to botrytis. The moisture on the grapes can also lead to rot on berries
which had been damaged by birds, insects or mechanical causes. In that case
a treatment against botrytis can be advisable. Products based on
bicarbonate or silicate have some effect and have only short wait periods.
Low percentages of “clean” botrytis infections aren’t necessarily a problem
when it comes to white grapes. You all know about nobel rot Rieslings -
well it isn’t limited to this variety, and it doesn’t mean you have to make
it a sweet wine either. However, there are  some caveats to be regarded
when you make a wine from grapes affected by botrytis: rule of thumb is
1g/hL activated charcoal per percentage of botrytis grapes on the juice.
Very thorough clarification of the juice either with enzymes, bentonite,
filtration or a combination of these methods. Keep an eye on your pH and
add acid if necessary. Use a strong yeast strain, potentially with killer
factor or jumpstart the fermentation with some lees from another clean
fermentation.

Botrytis in red grapes is problematic since the laccase enzyme of the
fungus leads to premature browning of the wine. Unfortunately laccase is
mostly unaffected by SO2 and can’t be deactivated this way. Must
pasteurization is effective but few wineries have the equipment and it
affects the wine style negatively. Bentonite does help, but isn’t practical
in the must stage. In the wine stage it does strip out a lot of color and
should be used with caution.
Best bet is to meticulously select and sort your grapes at harvest. In bad
cases it may make sense to have a crew go through the vineyard and cut all
rotten fruit to the ground before harvesting the good grapes. A second
sorting through a sorting table can be very useful.
If you feel a botrytis infection is already in your vineyard, treatments
with carbonate (not bicarbonate) may help. Carbonate is caustic and burns
the fungual spores and hyphens by its high pH. But be careful it can also
damage the leaves, your eyes, metal and even glass on your tractor, same is
true for silicate based products.

I have still two vineyards hanging. I hope it will go well.
Good luck everyone!

Jonathan

On Fri, Oct 22, 2021 at 14:55 GREGORY F piszczatowski <soqueltax at msn.com>
wrote:

> I use a leaf blower after a rain.
>
> I’m fermenting separately then deciding if I can: (1)  blend lowering
> overall alcohol level by the level of that 20%, (2) bottling a “rose” (I’ve
> heard it is good on ice on hot summer days),  or (3) dumping it. Anyone
> know how to preserve when bottling grape juice?
>
> At April 15 this year my shoots were 2” tall.  Greg P Soixante Vineyard
> Soquel.
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows
>
>
>
> *From: *TONY PIAZZA via VASCM <vascm at lists.kkn.net>
> *Sent: *Friday, October 22, 2021 2:41 PM
> *To: *Kenneth Challenger <ironrosevineyards at gmail.com>
> *Cc: *Vascm <vascm at lists.kkn.net>
> *Subject: *Re: VASCM: Harvest Advice Please
>
>
>
> There are probably a number of us who haven’t harvested yet who would be
> interested in hearing the thoughts of the experienced experts in our group
> about maneuvering around this rain. Thanks for putting the question out
> there.
>
> Sent from my iPhone
>
>
>
> On Oct 22, 2021, at 1:39 PM, Kenneth Challenger <
> ironrosevineyards at gmail.com> wrote:
>
> 
>
> Sent from my iPhone
>
>
>
> *To:* Vascm <vascm at lists.kkn.net>
> *Subject:* *Harvest Advice Please*
>
> Hi all,
>
> I have about 20% of our Chardonnay still on the vines. This section of the
> vineyard is  always 2-3 weeks behind the majority of the vineyard. The
> first harvest was on 8 October at 23.4 Brix. The remaining 20% is up to 22
> Brix. I sprayed Rally last Monday anticipating the rain. The question is,
> should I pick now or run the risk of infection while waiting until I get
> close to 23 Brix?
>
> Any advice is appreciated since I haven’t faced this weather situation
> before.
>
> Kenneth Challenger
> Iron Rose Vineyards
>
>
> Sent from my iPhone
>
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-- 

Jonathan M Goodling M.S.

Vineyard Manager

650 304 6978

                800.975.7191

www.HouseFamilyVineyards.com <http://www.housefamilywinery.com/>
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