birch sap wine - stuck fermentation

[pmcginley]

greetings all,

i have been experimenting (with fairly good results) over the last several years with wines and ciders using ingredients from my property and spontaneous fermentation. my best result so far, imo, was my 2014 birch sap wine, which came out crisp, fresh and dry, so i was excited to get on my 2015 earlier this spring. this was my recipe:

20 liters reduced birch sap
6 kgs sugar
1.2 kgs raisins
6 lemons

last year it fermented out beautifully, but this year it has stuck at 1.040 (started at 1.120). i have attempted to restart it several times with no success; once with a restart mixture, once with a champagne yeast, and once letting it settle fully, racking, and adding yeast nutrient and a 'rouge' yeast (which the guy at the wine shop said was needed for the higher acidity of birch sap). i've also tried warming it and aerating it. it hasn't moved from 1.040 since june.

the only thing i can think of that is different is how much i reduced the sap. in 2014 i didn't take very good notes, i just know that i collected the sap and reduced it 'a little', probably from 23 or 24 liters down to 20. this year i reduced 29 liters down to 20.

right now what i have is drinkable as a dessert wine or as a spritzer mixer, but it's sweet for my tastes. but i can't think of what else to try. does anyone have any advice for me? do i have any hope of getting this wine started again, or should i just give up and accept it as is?

thanks!
patrick

 

[Yooper]

It sure seems like you've tried everything. I'm not sure what you mean by a restart mixture, but I assume it's a yeast starter?

It could be that boiling and reducing the syrup that much caramelized the sugars and made them less fermentable, but that seems like a long shot. 1.040 is pretty darn sweet. It won't help this time, but for next time start with a much lower OG, like 1.085 or so, and add more syrup later to incrementally feed the wine, and push the ABV a bit. For now, I just can't think of anything you didn't try. I'll keep pondering it, though.

It sounds like it's good, but just too sweet?

 

[cooper]

You could also make another super dry batch and then blend them into something less sweet.

 

[pmcginley]

It sure seems like you've tried everything. I'm not sure what you mean by a restart mixture, but I assume it's a yeast starter?

to be honest, i'm not entirely sure what it was, and i haven't kept the packaging. :smack: it was some kind of all-in-one mixture specifically for restarting stuck fermentation, or so it said. it didn't introduce new yeast, it was just meant to somehow give a kick to the yeast that was there. the wine-shop guy said if it didn't work, then the yeast in my solution was definitely all dead, and i should then pitch a new yeast. in any case, it didn't work.

It could be that boiling and reducing the syrup that much caramelized the sugars and made them less fermentable, but that seems like a long shot.

this is exactly the sort of thing i was wondering about. i *did* boil it for quite a long time. it *did* turn it a more golden color. i'm thinking it did caramelize, but i wasn't aware of the effect that could have on fermentability. is that a thing? are caramelized sugars not fermentable?

1.040 is pretty darn sweet. It won't help this time, but for next time start with a much lower OG, like 1.085 or so, and add more syrup later to incrementally feed the wine, and push the ABV a bit. For now, I just can't think of anything you didn't try. I'll keep pondering it, though.

thanks. yes, that sounds like a good strategy, i'll try it next spring. i also won't reduce the sap.

It sounds like it's good, but just too sweet?

yes, that's exactly what it is. very tasty, but too sweet. i'm not even concerned about the ABV, it's already at 10.5%, but i'd like it to be less cloying. if there's no way for me to ferment out the remaining sugars, are there any other nifty tricks to cut the sweetness? add more lemon, perhaps?

 

[pmcginley]

You could also make another super dry batch and then blend them into something less sweet.

good idea, yes, i was thinking i might blend it with something, although there's no more birch sap to be had now until next spring. anyway, the 2014 came down practically to 1.000, and is great that way, so maybe i'd be better off blending it with something else that's not so nice that dry. i've got a batch of blackcurrant wine going now, maybe that could be a candidate.

 

[stella_tigre]

Would there be an issue with pH?

 

[sablesurfer]

Make a birch port?

 

[pmcginley]

Would there be an issue with pH?

possibly. i have no experience with pH. how would i measure and interpret that? is it something that could be different between last year's batch and this year's?

 

[pmcginley]

Make a birch port?

that also sounds like an interesting idea. is 1.040 about right for a fortified wine? so if i added, say, 1 part spirit at 40% ABV to 3 parts of my wine, i'd get something around 18% (that would also be a little less sweet). is that the idea?

 

[sablesurfer]

that also sounds like an interesting idea. is 1.040 about right for a fortified wine? so if i added, say, 1 part spirit at 40% ABV to 3 parts of my wine, i'd get something around 18% (that would also be a little less sweet). is that the idea?

LOL...sorry I was totally making random suggestions. I love me some good port though and I would think that if too sweet as a wine, why not experiment.

I'd go with a redneck freeze distillation to try to make it up to the numbers, but that would also concentrate the flavors. (Judged a beer competition where a freeze distilled stout medaled.)

I was drawn to your post because I was studying birch syrup production about same time as we vacationed to Alaska and I was like....Ooooooooo.....

 

[stella_tigre]

possibly. i have no experience with pH. how would i measure and interpret that? is it something that could be different between last year's batch and this year's?

They sell ph strips at the home brew stores, and personally I've never had to deal with a problem. Just trying to remember what can cause a stuck fermentation. If the syrup had a higher (or lower, depending) ph after being concentrated more, the ph in this wine might be different. I know it can be an issue with mead.

 

[pmcginley]

They sell ph strips at the home brew stores, and personally I've never had to deal with a problem. Just trying to remember what can cause a stuck fermentation. If the syrup had a higher (or lower, depending) ph after being concentrated more, the ph in this wine might be different. I know it can be an issue with mead.

and if i did determine it to be a pH issue -.is there anything i can do about it? how do i adjust pH?

also, how do i determine what the pH *should* be?

particularly curious about this question now, since i've just started a mead as well.

 

[pmcginley]

I was drawn to your post because I was studying birch syrup production about same time as we vacationed to Alaska and I was like....Ooooooooo.....

i highly recommend trying this wine recipe - as i mentioned, i think my 2014 birch sap wine is the best thing i've ever made. dry and crisp, no sourness, and a very particular earthy taste. it also improved dramatically after 6 months bottled.

 

[Yooper]

this is exactly the sort of thing i was wondering about. i *did* boil it for quite a long time. it *did* turn it a more golden color. i'm thinking it did caramelize, but i wasn't aware of the effect that could have on fermentability. is that a thing? are caramelized sugars not fermentable?

Yes. Caramelization can definitely make sugars less fermentable.