Should grapes with some mold be trashed?

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Segarram

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I got some Chilean merlot grapes and I was about to put them in 6 gallons of merlot juice and I just noticed they have some mold on them. I'm fairly new to winemaking and was about to throw them in the trash but decided to post a new thread to see if there is anything i could do to still use the grapes?

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vernsgal

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I don't think I'd use them. Your 1st instinct is probably correct.Otherwise you could ruin your juice. IMO.
 

mvcrews

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Get rid of all visible mold and immediately apply a minimum of 50 ppm s02. How many grapes are we talking about (what % rot)? Could you do separate fermentations? If not, you have to decide if the benefits of fermenting on skins and seeds outweigh the negative effects of mold. There's still ample fermentable sugars and phenolics in the moldy fruit, but there's also less than desirable aromas as well as by products that make the yeast unhappy.
 

Segarram

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Get rid of all visible mold and immediately apply a minimum of 50 ppm s02. How many grapes are we talking about (what % rot)? Could you do separate fermentations? If not, you have to decide if the benefits of fermenting on skins and seeds outweigh the negative effects of mold. There's still ample fermentable sugars and phenolics in the moldy fruit, but there's also less than desirable aromas as well as by products that make the yeast unhappy.
One lug (18 lbs) of grapes. I'd say it had a little less than 1/2 a cluster of grapes with mold on it, 4 or 5 small patches on the top layer. The smell is not bad at all.

Last night I scooped out the moldy patches, transferred the grapes to a clean sanitized bucket, and then added 7 to 8 crushed campden tablets to the grapes in anticipation of adding the grapes to the 7 1/2 gallons of Merlot grape juice I have in a separate bucket.

Is there anything else I could/should do?
 

dralarms

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Just watch it to see if the mold reappears.
 

JohnT

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One lug (18 lbs) of grapes. I'd say it had a little less than 1/2 a cluster of grapes with mold on it, 4 or 5 small patches on the top layer. The smell is not bad at all.

Last night I scooped out the moldy patches, transferred the grapes to a clean sanitized bucket, and then added 7 to 8 crushed campden tablets to the grapes in anticipation of adding the grapes to the 7 1/2 gallons of Merlot grape juice I have in a separate bucket.

Is there anything else I could/should do?

I think you sould be ok however, we are talking about mold here!

I would definitely follow MVCREWS advice and nuke it with the k-meta.
In future, I would recommend the following.. When in doubt, toss it out!
 

grapeman

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It sounds like you already added k-meta in the form of the campden tabs so you should be fine. Ideally you should have remove the offending cluster before crushing and then not have to worry about it. It may have been botrytis and some of that is alright in small amounts. Some botrytis bunch rot is very stinky and should never be included.
 

mvcrews

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Use a robust strain of yeast and get it started fermenting. The mold won't be able to live with the active yeast and their byproducts (alcohol and c02).
 

Segarram

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Use a robust strain of yeast and get it started fermenting. The mold won't be able to live with the active yeast and their byproducts (alcohol and c02).
My original goal was to put the Merlot grapes into 7.5 gallons of Merlot juice. Should I do that 24 hours after adding the K-meta or do you suggest I ferment them separately?

Thanks for your input.
 
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CBell

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That's a tough question because you obviously want to ensure there is no further mold in the grapes before you mix them with your juice, but you also need to get those grapes fermenting ASAP so the ferment will make an unsuitable environment for your mold.

I might be tempted to add yeast to the grapes in 24h and get it started fermenting, make sure there is no mold growth for a few days and then dump the whole fermenting thing into your juice in a few days when you are confident the mold situation is taken care of.
 

mvcrews

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The amount of s02 you added won't inhibit fermentation in the 7.5 gallons of juice but it might inhibit fermentation for the 18 pounds of grapes...

I think others may disagree with me here but I would ferment them together as I feel the benefits fermenting red wine on the skins and seeds outweigh the risks of using moderately compromised fruit.
 

Segarram

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The amount of s02 you added won't inhibit fermentation in the 7.5 gallons of juice but it might inhibit fermentation for the 18 pounds of grapes...

I think others may disagree with me here but I would ferment them together as I feel the benefits fermenting red wine on the skins and seeds outweigh the risks of using moderately compromised fruit.

Added the grapes to the juice last night and added two packets of Premier Cuvée yeast to about 8.5 to 9 gallons of Merlot. Checked it this morning and there are signs of fermentation. Below is a picture of the primary must about 30 minutes after adding the yeast.

merlot_must.jpg
 
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joea132

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I've added 90ppm to my ugly looking grapes when I really go nuclear. I do 50ppm for normal grapes. Good to see you're going good.
 

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