Stuck Zucchini! Help!

[DrGriz]

Last week (3/27) I started a zucchini wine from the cut/frozen zucchini my daughter (who lives in a great growing climate) gifted me for the purpose. 6 lbs zucchini in a bag, along with 1 inch of ginger root, 1 tsp Fermax, 3/4 tsp energizer and 1/2 Pectic enzyme were added. Sugar and water to bring it to a gallon plus and an OG of 1.090 in a 2 gallon bucket. I treated with K Campden overnight, and kept it in the relatively warm upstairs living area as I have other wines. The following day I pitched Red Star Premium Blanc (a champagne yeast was recommended in the recipes I noted). I got foaming and what I have come to expect in the first 12 hours and overnight. At 24 hours SG was 1.070. Tasted like pleasant sugar water. Stirred a couple times a day.

At 48 hours from pitching the yeast, all activity had stopped. SG stayed at 1.070. On 3/30, no movement so I checked pH which was 4.7. I added acid blend to bring the pH to 3.8 and on 3/31 added more to bring the pH to 3.5. Later that day I repitched with Lalvin EC1118 and pulled out the net bag with the zucchini, squeezing as usual. No movement. If there was yeast it was on the bottom. This went on until yesterday, when I pitched again with prehydrated overnight (fed with sugar) EC1118 and placed the bucket in the sun where it would get a little warmer. I also put in another teaspoon of nutrient. This time it quickly grew a 1/2 inch thick yeast cap. Smells like yeast! Good, I say! But still only slight bubbling yesterday (you had to look close to see).

This morning we have a thick yeast cap, no bubbling, and an SG of 1.070. Smells like yeast and at no point were there any bad smells.

I'm new at this and so far this is the first time I have had wine completely stuck for this long. I have done other wines (Mt. Ash, huckleberry, apricot, rhubarb, cherry, along with some perry from juice) and not had this happen. The PerryCherry and Cherry "ciders" I started the same day as the zucchini wine were nearly finished in 48 hours.

I'd love suggestions!

 

[winemaker81]

It sounds like you made good corrective actions. Stir the must 3 times per day, and give it another day before checking SG again.

 

[DrGriz]

"So you're saying there's a chance?"

After I posted and before your response I sprinkled some energizer in and stirred it, thinking there might be something the nutrient missed. It has a good yeast cake going with anemic bubbling this afternoon. Here's a pic.

Thanks for the help and encouragement.

 

[winemaker81]

I've had wines that shows very little visible activity have the SG drop like a rock, while others with thick foam had the SG s l o w l y decrease. This is affected by the yeast strain, the wine type, the solids in the must, and probably other factors. If the SG is dropping, it's good.

Why yours stuck at 1.070? Yeast is a living organism and it doesn't always act consistently or in a way we want. There are factors we don't necessarily understand, and it could be that Mother Nature and Dionysus are messing with you. They do that from time to time.

Patience, Grasshopper

...

@Ohio Bob ... there's another one! I bet I say that one ten times per month!

 

[DrGriz]

I've had wines that shows very little visible activity have the SG drop like a rock, while others with thick foam had the SG s l o w l y decrease. This is affected by the yeast strain, the wine type, the solids in the must, and probably other factors. If the SG is dropping, it's good.

Why yours stuck at 1.070? Yeast is a living organism and it doesn't always act consistently or in a way we want. There are factors we don't necessarily understand, and it could be that Mother Nature and Dionysus are messing with you. They do that from time to time.

Patience, Grasshopper

...

@Ohio Bob ... there's another one! I bet I say that one ten times per month!

What was so interesting is that it dropped the first night from 1.090 to 1.070, and then locked up. The yeast that was there dropped to the bottom. It was as though it was either contaminated with something or ran out of some essential vitamin or mineral. When it didn't respond to my first ministrations, I really worried. I do think it likes me to keep the bucket in the sun, since it seems to bubble more than overnight. Maybe I'll put it on a hot pad!

Thanks so much for the encouragement!

 

[winemaker81]

How much did the temperature drop at night? A big drop, e.g., > 10 F, can stunt a fermentation. Having a stable temperature can be more important than the temperature itself. My fall ferments are at cellar temperature, which is 63 to 67 F (17 to 19 C).

 

[DrGriz]

How much did the temperature drop at night? A big drop, e.g., > 10 F, can stunt a fermentation. Having a stable temperature can be more important than the temperature itself. My fall ferments are at cellar temperature, which is 63 to 67 F (17 to 19 C).

I had wondered about that. Well, the room has been between 67 at night and 75 during the day (mostly passive solar). I did have a woodstove fire going one of those nights early on because it was really cold outside (21F). So it was possibly warmer that night in the room.

I have been wondering about stunting due to temp fluctuations like that, but that's how we live and no other wine has done this so it's new. I think a hot pad might help. I'll try it anyway unless someone thinks it's a bad idea.

Thanks!

 

[winemaker81]

Your temperature is bouncing, so it's a likely cause. Why this batch and not others?

No idea. There are biological and chemical processes occurring that we understand, and probably more that we don't. I chalk it up to one of the unknowns of life and just keep making wine.

 

[DrGriz]

Your temperature is bouncing, so it's a likely cause. Why this batch and not others?

No idea. There are biological and chemical processes occurring that we understand, and probably more that we don't. I chalk it up to one of the unknowns of life and just keep making wine.

It's part of the fun! And the mystery when things don't go the way you plan. It was starting to get boring!

I have learned so much from reading on this site these last few months! What a font of knowledge!

Thanks again!

 

[BigDaveK]

Just throwing this out there...
In the herbal remedy world ginger is a very well known antimicrobial (among other benefits). Because of that most sources suggest simmering ginger (and onions and garlic and others) before making wine to neutralize it.

 

[DrGriz]

Just throwing this out there...
In the herbal remedy world ginger is a very well known antimicrobial (among other benefits). Because of that most sources suggest simmering ginger (and onions and garlic and others) before making wine to neutralize it.

Ahh! Thanks for pointing that out!

 

[DrGriz]

So I placed the plastic bucket on an old heating pad on the lowest setting overnight. This morning, the must temperature is 92F (it started out at 75F last night, and I had some bubbling as noted).

This morning it looks like an active must, and the SG is now 1.050 down from 1.070 yesterday AM.

I guess that's the secret!

I don't know why this yeast/must combo likes warmer temps. I am worried that 92F is a bit higher than what most people make wine, although I don't know if it is out of range. I know that fermenting wine is exothermic, but I haven't measured any temperatures here to see what is normal at my house. It will be a cloudy day, so probably the house temp won't be as warm and there's no placing the bucket in the sun today.

Should I leave it on the pad or take it off and see what the temperature does?

 

[cmason1957]

I would certainly take it off the heating pad, 92F is way high and may stress your yeast significantly.

 

[DrGriz]

I would certainly take it off the heating pad, 92F is way high and may stress your yeast significantly.

Now I am afraid of it cooling off too fast and getting stuck again. Room temp is well more that 20 degrees lower!

 

[Rice_Guy]

* I would prefer fermenting at 60F than 80F. High temperature increases the nutrient demand from the yeast, ,, and the risk of reduced sulfur taste. A 10F daily cycle within yeast tolerated temperatures isn’t too bad.
* I like the note above about ginger being partially toxic.
* yeast requires oxygen for reproduction down to 1.050. Yeast need micronutrients so I like organic nitrogen (Fermaid). Yeast are tolerant down to pH 2.8 where as many bacteria are tolerant down to 3.5, to encourage yeast I would be below 3.5 always! microbes grow in waves of types, one choice is that an organism that likes high pH was reproducing.
* Using six pounds of zucchini plus water you had more of a sugar wine. When doing zucchini I freeze then press juice out. ex of juice 1.022 and 1.014 gravity; pH 6.96 and 6.53; TA 0.03%. ,,, there isn’t much stuff to grow on.

 

[DrGriz]

* I would prefer fermenting at 60F than 80F. High temperature increases the nutrient demand from the yeast, ,, and the risk of reduced sulfur taste. A 10F daily cycle within yeast tolerated temperatures isn’t too bad.
* I like the note above about ginger being partially toxic.
* yeast requires oxygen for reproduction down to 1.050. Yeast need micronutrients so I like organic nitrogen (Fermaid). Yeast are tolerant down to pH 2.8 where as many bacteria are tolerant down to 3.5, to encourage yeast I would be below 3.5 always! microbes grow in waves of types, one choice is that an organism that likes high pH was reproducing.
* Using six pounds of zucchini plus water you had more of a sugar wine. When doing zucchini I freeze then press juice out. ex of juice 1.022 and 1.014 gravity; pH 6.96 and 6.53; TA 0.03%. ,,, there isn’t much stuff to grow on.

Thank you so much for this input. I did squeeze out juice. There was some in the bags of frozen zucchini, and then I squeezed out juice after soaking in must in a net bag for 3 days per the recipe I used (Bernard Smith's from here. https://www.winemakingtalk.com/threads/country-wine-marrow-aka-courgette-aka-zucchini-wine.66111/).
Maybe late, but the pH after two days was 4.7 and I knocked it down to 3.5. I probably should have done that before I pitched the yeast, true?

I had Fermax instead of Fermaid, but I have read that Fermax is a 1:1 substitute for Fermaid K. Is that OK?

At this time, the yeast dropped and stopped fermenting when the room temp was 74F and below. I am not sure whether taking it off the heating pad will cause it to stop again. Should I just go for it and let it drop to Room Temp or whatever temp the fermentation goes to without the pad?

 

[Rice_Guy]

Fermax can provide micronutrients. It is a good choice. ,,, In the ideal world one adjusts everything (pH) at the start. The logic is that it can temper and we can take accurate readings. My experience with lemon is that it is inefficient at reducing pH, and to get target with something like mulberry might require 25% to 50% lemon. AND in the end is it more of a lemon wine. ,,, As always what is your gravity? If you are 1.000 the heating pad is done. We want it finished. There should have been slower fermentation at 60F which might require two to three weeks to complete. Yeast really are hearty buggers.

 

[DrGriz]

Thank you so much for asking!

Well, for fear of cooking the wine, I turned off the hot pad yesterday AM, and watched the temperature during the day. The must continued vigorous bubbling that looked completely normal to me. The temperature gradually dropped from 92F to 79F over 12 hours. Things continued to look like they were going well so I decided to let it go.

This morning the temp is 76F (room is 71F), pH is 3.5, and SG is 1.011. As @winemaker81 said, it dropped like a rock over 24 hours.

Pictured below is Must, before and after stirring.

The instructions say to add the lemon when I transfer to the secondary container, which I am supposed to do at 1.010 to 1.000. So we are close.

My inclination is to add the lemon and recheck the pH and taste the wine when I do the transfer. Maybe adjust further with acid blend if it needs it.

I will stir and rack the gross lees with the must and leave it to drop out in the secondary. I don't think it will hurt the wine to spend more time on the gross lees, unless someone thinks differently. Otherwise, it probably won't have much time on the lemon peel.

 

[Rice_Guy]

the instructions on racking below 1.010 could say “when it is convenient”. My normal target is between 1.020 and 1.010, wine is an art, not an exacting science.

 

[DrGriz]

the instructions on racking below 1.010 could say “when it is convenient”. My normal target is between 1.020 and 1.010, wine is an art, not an exacting science.

Just so! It wasn't convenient for me to rack this morning when the SG dropped so quickly to 1.011, but I went ahead this afternoon and it's in the carboy at 1.006 and still going strong. Maybe for this I did want to wait to keep it from foaming over in the carboy.

The pH was vacillating between 3.4 and 3.5 after adding the lemon peel and juice, so I knocked it down further to 3.3 with acid blend and it has a pleasant tart taste to it. I can taste the lemon and the ginger a little. Don't know that I can say there's much zucchini flavor, not that zucchini HAS much flavor. This wine will go back to the source. My daughter and her SO who doesn't really appreciate wine yet. He will enjoy this I think and then we can move him to more interesting stuff.

So it's not clear if the Fermax or the heating pad did the job of unsticking this wine, but I think I might keep the heating pad in mind if I get a stuck wine in the future.

Thanks to you and everyone for the input!