Reduless and H2S

[Rob S]

I have some Reduless and never used it before. I'm almost at the end of my fermentation with grapes and I encountered a bit of H2S odour starting around half way through the fermentation. I kept adding the nutrients in stages up to one third sugar depletion, did the splashing during punching the cap to help it volatilize off and has improved the situation, but could always detect just a bit from then on. I took a sample this morning and smelled the nose and tasted it and cannot detect sulphur on the nose and wine tastes good, so I'm pleased with it. Yet I have Reduless, so wondering if it a good idea to add Reduless even though the nose seems ok in case there is a little bit there that could be masking some of the nose and as a precaution for any Disulfide and would clean up any residue in the wine after pressing and leave it for 2 days and rack it off at the same time as racking off the gross lees?

This is not the first time it happens a little and the wine usually turns out fine, except one time 15 years ago when one batch of wine had a serious problem, and rectified the batch with a very minute measured amount of copper sulfate, but wine's nose was not very good after all of this.

Thanks,

Rob

 

[stickman]

I would normally say don't add copper unless you detect a real problem using a side by side bench test; copper has some negative side effects if used in excess. On the other hand, I have seen literature suggesting the use of very small amounts of Reduless, 1g/100L just after press, and again the same dose a few days before the ML completion racking. We're talking about artistic quantities here, but I've never tried the method, so take it for what it's worth.

 

[Rob S]

Thanks and I agree. I just spoke to Scott Labs and the source may be grapes that have been sprayed with sulphur given I seem to have added enough nutrients, but can't be sure. The consultant also mentioned there are other factors due to climate that is changing, etc. He also suggests I do some bench trials with Reduless and see if the nose changes, if not, then no H2S in the wine or may be some other sulphur compound, re the H2S derivatives. He did say a little bit can mask some of the bouquet so worth trying with bench trials. He said some wineries are adding 3-5 g per HL of GoFerm when H2S is detected during the fermentation and makes yeasts happier. I'm surprised at this. He said this practice has helped sometimes. Did not find anything on this practice by Googling as of yet.
He suggests I try any of these products: Kleenup or Rescue (not sure of the spelling on this product). These are better alternatives than using copper.

Rob

 

[1d10t]

It seems to me I've read of some beer style where it is considered good to have that smell because it means 'it' is being 'driven off'. I'm starting to wonder if it is ALWAYS caused by stressed yeast.

 

[Rob S]

Thanks, you raise some very good questions. I've just phoned an Eologist for Lallemend and she has been very helpful. After explaining what I will below here in a moment, to her over the phone, it looks like the 60 ppm of SO2 added at the crush, yikes!

 

[Rob S]

Sorry, pressed the return key, please allow me to continue:
Thanks, you raise some very good questions. I've just phoned an Eologist for Lallemend and she has been very helpful. After explaining what I will below here in a moment, to her over the phone, it looks like the 60 ppm of SO2 added at the crush, yikes! is part of the source of the problem. I use Dynastart, nothing wrong with this product, but she said if I should now use GoFerm Protect, it would help protect the yeasts somehow (not sure the reason - but ok) and worth trying.

The grapes (80 L of must) are from Spain, Tempranillo, came as frozen must. The pH was 4.03 and TA was 4.6. Added 2 g\L tartaric acid to bring pH to 3.7 and for TA could not get accurate reading despite my pH meter and titration, so estimate it to be around TA of 6. So that is enough adjusting for now at this point - will see later after fermentation is over. Brix was 23, YAN was 127 according to fermaldehyde kit and doing a titration with pH meter. Yeast is D254, medium N requirement with this yeast, so target total YAN was 350 mg \L. Punched 3 times a day and helped blow off volatility of some H2S. Added Fermaid K and O after Cap and started to get H2s around mid way through fermentation, added some more nutrient and helped, then next morning when got up, yeast were complainng again, added to more until 1\3 sugar depletion, this helped again. This is all good, but everyone hopes not to get any H2S or lessen the problem - always looking to do it better next time. Looks like it is not only us hobbyists, as wineries have the same challenges.

 

[stickman]

Just for comparison I ran numbers as if I were using this must. At 23brix I estimate the required YAN to be around 250ppm, therefore needing to add 123ppm YAN, Fermaid K is about 10% YAN, so in this case I would normally be adding 1.6 g/gal Fermaid K, plus 1.4 g/gal DAP based on estimated finished wine volume not must volume. If you decided to use only Fermaid K to supplement 123 ppm YAN, you would need about 4.6 g/gal which would exceed the Lallemand recommendations.

The other wild card is the nutrient addition timing, most recommendations suggest cap rise or 1/3 sugar depletion, that's fine under normal conditions, but when the initial YAN is below 150ppm the first YAN addition should be closer to inoculation, especially when must has spent time in the 50F to 55F range, during this time wild yeasts are consuming the available nutrients, and by the time you pitch your selected yeast, the nutrient content is significantly below your initial measurement, so the first nutrient addition at cap rise ends up being too late, and now your selected yeast has had to expand in a nutrient deficient must leading to a stressed population generating H2S.

Obviously the non H2S producing yeast is a no-brainer for reducing the risk of H2S, at least it eliminates most H2S headaches, but it doesn't eliminate all nutrient related issues like stuck fermentation or VA production etc.

 

[Rob S]

Thanks, adding some nutrients earlier makes sense as you suggest. I will try next time. However, I don't agree with the much lower amount of YAN you suggests based on a couple of published documents I have found. It bases it on a list of yeasts and at various brix levels. It comes out to between 300 to 350 total ppm of YAN for D254 for 23 Brix. So I'm confident I'm not over adding.

 

[Rob S]

Re-reading the article from Nanaimo Winemakers: http://nanaimowinemakers.com/adding-nitrogen-fermentations/
it depends on the approach we are using. I think neither of us is incorrect when it comes to the amount of YAN to add. Your approach is based on the average amount needed by yeast around 250-300 ppm of YAN at 23 Brix. Whereas my approach is based on the article where I provide the link, that factors in the particular yeast's Nitrogen requirement. For example the D254 according to the article requires a multiplier of 1.2, that would raise the YAN to between 300 and 350 ppm. But which of the two approaches is better still remains one of my unanswered questions.

 

[NorCal]

Redulees contains copper, which I believe is their active ingredient that removes H2S. Redulees contains a very small dose and probably below the limits even if all the copper stays suspended in the wine. I don’t think this is a decision you need to make now. If it’s not broken, don’t fix it. If you get some H2S smells later on, you can address it.

A late spraying in the vineyard can cause H2S as mentioned above, so may not have anything to do with what you did during fermentation.