What to do with these Grapes ?!

[hector]

You seem to believe for whatever reason that a low pH means H2S. Proper yeast selection minimizes H2S. I do thousands of gallons of wine, not carboys of it, so I do have a bit of experience.

I'm very grateful to hear from an experienced winemaker , dear Grapeman .

The yeast strain I use is "Pasteur Red" from "Fermentis" .

Although , one of its charachteristics is "Low production of H2S" , I don't know why I can smell

H2S from the second day of fermentation , if the low pH is not the main Cause .

By my first batch , as I had the same problem , I asked an experienced wine councellor

( although he doesn't give advice for free , but he was so kind and did it for me ) .

He said that the yeast is under Stress because of low pH and emits H2S .

Hector

 

[Julie]

Well the best advice I am going to give you is stop making wine from those grapes. Find something else to make wine out of.

 

[hector]

Hector you have not told us what kind of grapes you are using yet.....

These grapes are sold in stores as table grapes . They are called "Black Grapes" here and are not dealt like

the certain types for winemaking as you have in the U.S.

Although , it's against the law in my Country , but there are some people who love drinking Beverages and

try to make some privately at home . Specially those who have a Religion other than the main Religion ( Islam ) in my Country .

But , the problem is that they don't do it the same way we do . For example , they know nothing about sanitization and

do nothing about it . They also don't deal with the S.G. , SO2 , pH and so on . They don't even use any yeast .

They just crush the grapes ( Unwashed ) and leave it in a closed container for 40 days , then strain and drink it .

So , would you still call them "Skilled Winemakers" ?!!

That's why I joined this Forum to grow my knowledge and experience about winemaking .

By the way , I wish you hadn't mentioned my Country here , because I'm not sure how others would react in the Forum .

I've had some problem in another Forum , as I only said that there are no wine and brewing supply shops

here because it's against the law .

Hector

 

[hector]

The main reason for H2s is improper nutrients for the yeast or low 02 levels for your yeast to thrive in. Some of these yeasts are notorious fpor this H2S problem like Red Star Montrachet but I use it all the time and with proper nutrient levels and plenty of 02 I dont have any of these problems.

I use "Pasteur Red" and added enough nutrient to the Must ( 1 teaspoon per Gallon ) , but befor pitching .

Hector

 

[Julie]

Hector,

We are all a bunch of honest people on this forum. No one here wishes you ill will but you also need to understand no one here feels comfortable helping someone else break the rules of their country especially when you don't want to take any of that advice.

I have read thru these posts and you have some very experienced winemakers trying to help you out and you have done nothing but argue with them.

Take a sample of your wine to your "wine councellor " and ask him what is wrong with your wine.

 

[arcticsid]

Hector, put the lime in the coconut and shake it all up!


geeze louise!

 

[hector]

We are all a bunch of honest people on this forum. No one here wishes you ill will but you also need to understand no one here feels comfortable helping someone else break the rules of their country especially when you don't want to take any of that advice.
Take a sample of your wine to your "wine councellor " and ask him what is wrong with your wine.

Thanks a lot !

I always appreciate your and others' advice .

You misunderstood the situation in my Country . We hate Those who set such laws for us .

In fact , they themselves smuggle wide range of Beverages into the Country and therefore they are too expensive here .

I would like you to understand that neither you nor others in this Forum are helping me to act against the law

in my Country , as I'm living thousands of miles away from you and just trying to improve my knowledge about winemaking .

I do it privately at home and we drink it along with the family and friends .

It has nothing to do with any law in my Country . Believe me , please .


I'm told in this Thread that to let the wine ferment and then adjust the pH . As I said , it's emitting H2S and

as far as I know , it must be dealt with as soon as possible . Otherwise , it will be very hard to get rid of it .

Therefore , I brought up the pH to 3.5 by adding Potassium Carbonate and pour it several times from one

bucket to another one .

But , what I have now is an oxidized wine , as I can smell "Ethyl Acetate" now .

By the way , the Councellor lives in the U.S. , I talked to him once on the phone two years ago and sent him some E-mails .

Hector

 

[Manimal]

If you have a noticeable EA odor, it may blow off as fermentation progresses. I've experienced quite a few fermentations where EA is noticeable at the beginning but not detectable by the end of fermentation. The CO2 will carry any esters with it as it bubbles out of the wine and will heighten the perception of them.

I'm a little confused by how your pH would decrease so dramatically as the juice soaks with the skins. Generally, acids are released in the juice easily and as the wine soaks with the skins the pH will rise due to the gradual release of of potassium. I think that your pH meter is not giving you good readings.

If you are making small batches of wine, you can probably get by using your palate more and worrying less about pH readings and strict measurements. I work at a high-end commercial winery and am very aware of the importance of lab analysis of musts/wines and making adjustments based on solid data and I am familiar with all standard lab testing procedures. However, when I make wine at home, I tend to make pretty small batches and as such there is not a lot at stake. I don't have fancy lab equipment (no pH meter, no method of SO2 measurement, no titration equipment, etc.) I make adjustments based on my palate and on experience and educated guesses. I have not had any serious disappointments with my homemade wines. I wouldn't recommend this approach for large batches where there is a lot of investment on the line or for people making wine on a commercial scale, but for the home winemaker making small batches it works just fine. (Also, if I could afford a good lab at home, I would definitely have one and use it... but the key word there is "good." Half-a$$ lab analysis is not worth the trouble and doesn't provide much more useful info than educated guessing.)

For the record, I am more than happy to help you out regardless of your location or the laws in your country.

 

[hector]

If you have a noticeable EA odor, it may blow off as fermentation progresses....

It's my pleasure to hear from you , too .

I just took a look at my batch and I can still smell ethyl acetate and it's getting stronger .

I'm also confused about the acid in the juice , but I think that there is nothing wrong with

my pH meter , since each time I test it with the buffer solutions , I get correct answers .

What would you say about H2S ?!

Hector

 

[Manimal]

What buffer solutions are you using? Standard wine lab buffers are pH 7 & 4. If you are calibrating with buffers outside this range, you might get weird results. In addition, if your meter is only designed to have an accuracy range of 0.5 pH units or something like that, you're never going to get useful results for winemaking. Also, are you using a stir plate when you test the pH? And are you being careful to fully rinse off the electrode storage fluid prior to use? I know that these are all probably things that you're aware of but I'm pretty sure something is wonky with your pH readings so I'm grasping at straws.

As far as the EA goes, there is not too much you can do at this point. Just try to make sure the fermentation conditions are as easy on the yeast as possible to avoid excess stress which might aggravate your EA issues. There is still hope that it might blow off, especially if your fermentation temperature is relatively warm (ie. >20 degrees C.)

H2S can be the result of various issues. Yeast stress is one possible cause. Try to make the yeast as comfortable as possible with enough O2 at the beginning of fermentation and timely nutrient additions. However, there are other possible causes. Excess sulfur in the fruit is one possible cause. If the grapes are sprayed with sulfur fungicide close to harvest there may be elemental sulfur on the grapes which can cause H2S during fermentation. Also, you say that you add 100mg/L SO2 prior to fermentation... I think this is really quite excessive. This high level of sulfur pre-ferment might be responsible for your H2S issues... If you are going to inoculate immediately with a cultured yeast strain, you can get away with adding no SO2 prior to ferment since the wine yeast will take over the fermentation and out compete any native yeast. SO2 has little affect against most yeast species... it is more effective against bacterial activity in the must. Alternatively, and more conservatively, you can add about 50 mg/L and that will be plenty to protect against lactic bacteria spoilage prior to fermentation.

 

[hector]

What buffer solutions are you using? Standard wine lab buffers are pH 7 & 4. If you are calibrating with buffers outside this range, you might get weird results....

Just as Info : I studied Chemistry and I know exactly how to use a pH meter correctly .

I use buffers 7 and 4 and I always rinse the probe prior to calibrating and reading .
I keep it in a saturated KCl solution . It has an accuracy range of 0.1 pH units .

I don't think the grapes are sprayed with sulfur , however , I always wash them before crushing .

They are sprayed with sulfur only when they are going to be dried and sold as black raisins , because each time

I take a look at such raisins in a store , sulfur smell is easily detectable .

I added 100 ppm SO2 after crushing in order to have 50 ppm free SO2 in the Must , as it was the first time of adding SO2 .

I pitch the yeast 36 Hours later .

Hector