how to improve a blunt white wine?

[blumentopferde]

dear community!
its been a while since ive been posting here... but still hope you can help me with this issue:

i have an issue with my white wines: they taste blunt, indifferent, not fruity at all and i wonder what might be the reason, and how i could repair the wines...

wine no. 1 is low in tannin, rather low in acidity (about 5 gram per liter / 0,5%). the must had 21,5 brix at the start, but i dont know its final alcohol and sugar levels, as it had fermenting issues even though i used yeast food, and the fermentation stopped before all sugar was converted. from the taste i would say that it is somewhere between dry and semi-dry. the taste is blunt, indifferent, maybe somewhat yeasty, even though the wine is totally clear, and far from enjoyable...

wine no2 is a late harvest, quite high in color (brownish) and tannin and had high sugar and acidity levels before fermentation: 24,4 brix and 8g/l or 0,8% acidity. it also had fermentation issues and did not fully ferment. the taste is semi dry and quite acidic. apart from the higher acidity it tastes neutral and uninteresting. neutralizing some of the acid makes the taste less acidic but not more enjoyable.

as last years wine was very good and as we had a very warm and long summer i actually expected much more... but now i wonder what i could do with the wines to make them enjoyable and what might have been the reason for the bad results.

any ideas or suggestions?

thank you!
blumentopferde

 

[user 36973]

wine no. 1 is low in tannin, rather low in acidity (about 5 gram per liter / 0,5%). the must had 21,5 brix at the start, but i dont know its final alcohol and sugar levels, as it had fermenting issues even though i used yeast food, and the fermentation stopped before all sugar was converted. from the taste i would say that it is somewhere between dry and semi-dry. the taste is blunt, indifferent, maybe somewhat yeasty, even though the wine is totally clear, and far from enjoyable...

Low in tannin for a white is probably a good thing .

What grape is it? The acid could be corrected with another 2g/L of tartaric acid or acid blend. The lack of fruit aroma suggests excess sulfites were used, the wine experienced oxidation, the quality of the juice was low, or perhaps the fermentation temp was too high. Various yeast strains may stop fermenting before all the sugar has been converted. This isn't always a bad thing though, depending on the wine. What fermentation issues happened?

You can attempt to fine it with the 2-step "super-kleer" agents. Be sure to always keep the sulfite levels high enough to protect the wine from oxidation and minimize headspace.

wine no2 is a late harvest, quite high in color (brownish) and tannin and had high sugar and acidity levels before fermentation: 24,4 brix and 8g/l or 0,8% acidity. it also had fermentation issues and did not fully ferment. the taste is semi dry and quite acidic. apart from the higher acidity it tastes neutral and uninteresting. neutralizing some of the acid makes the taste less acidic but not more enjoyable.

Brownish indicates oxidation. Are there notes of bruised apple or sherry, which would confirm this? The choice of yeast is important when working with late harvest fruit that are high in sugar and low in nutrients. Sounds from your description that the wine was oxidized. If that is the case, you can try some PVPP to soften the flavors and brighten the color. Otherwise, there is always sangria...

Might be worth the time to check your equipment to see if something has failed and should be replaced before it happens again next season.

 

[blumentopferde]

Hey, jgmillr1, thank you for your extensive reply!

@Wine1

Low in tannin for a white is probably a good thing .

I have the suspicion that it might be too low. I pressed the grapes directly without any mash fermentation. Could it be that my grape varieties require more contact with the skins to develop their aroma?[/QUOTE]

What grape is it?

it's a mix of various varieties, including Gutedel, Muskateller, Traminer, Sylvaner, Bouvier and Welschriesling. A so-called "Gemischter Satz".

The acid could be corrected with another 2g/L of tartaric acid or acid blend.

I will try this correction, but I'm more bothered about the lack of fruit aromas.

The lack of fruit aroma suggests excess sulfites were used, the wine experienced oxidation, the quality of the juice was low, or perhaps the fermentation temp was too high.

- Excess Sulfites: Possible. I produce very small quantities (about 5 liters per batch), could be that my scale is just not precise enough for the small quantities of sulfur that are needed.
- Oxidation: Possible. Before fermentation I added 0,1g/l (0,01%) sulfites to the must. The fermentation took about 3 months until I stopped it. The wine was in a closed glass carboy all the time, I just separated it from the sediments two times. Do you think, that this oxidation could occur under such conditions? Or do you think that it rested on the yeast for too long?
- Bad juice quality: Unlikely. The quality of the juice should be good. I removed stems and bad fruits and washed the grapes before pressing.
- Fermentation Temperature too high: Impossible. During the fermentation the ambient temperature was never above 15°C.

Various yeast strains may stop fermenting before all the sugar has been converted. This isn't always a bad thing though, depending on the wine. What fermentation issues happened?

The wine fermented slowly and with rising alcohol content the fermentation went slower and slower. That might be also due to the fact, that I fermented it in an unheated room and the ambient temperature sank also during the fermentation. I used cold fermentation yeast, that claimed to ferment at temperatures as low as 5°C but that might have been a too optimistic claim of the manufacturer.

You can attempt to fine it with the 2-step "super-kleer" agents. Be sure to always keep the sulfite levels high enough to protect the wine from oxidation and minimize headspace.

I thought these agents where just to clear cloudy wine. This wine is perfectly clear. Does it also improve the taste?

@Wine2

Brownish indicates oxidation. Are there notes of bruised apple or sherry, which would confirm this? The choice of yeast is important when working with late harvest fruit that are high in sugar and low in nutrients. Sounds from your description that the wine was oxidized.

I didn't notice any Sherry notes. It just tastes neutral and blunt. Actually I didn't do anything different during fermentation, compared to wine No. 1. The only big difference was that I harvested REALLY late - short before Christmas - and the grapes were already quite shrunk wrinkly until then. Could it be, that the juice was already oxidized - even though it tasted absolutely normal?

If that is the case, you can try some PVPP to soften the flavors and brighten the color. Otherwise, there is always sangria...

That sounds like an interesting product! My supplier doesn't have it, hope i can find it in hobby quantities somewhere in Europe...

Might be worth the time to check your equipment to see if something has failed and should be replaced before it happens again next season.

Good Idea! I checked, what I used during fermentation:
- potassium disulphite: I added 0,01% of potassium disulphate before fermentation to protect the must from oxidation. I don't thin that this can turn bad.
- Pectinase: I used pectinase to clear the must before fermentation. It was about 2 years old and I stored it in the refrigerator. The amount of pectinase to clear a must is very low - 0,005% - so I don't think that it can influence the taste
- Bentonite: I used bentonite on the must before fermentation to accelerate clearing of the must (only in the case of Wine No.1). I added it about 8 hours after the pectinase and gave it about 10 hours to sediment. I've read somewhere (can't find the source at the moment) that one can also add the bentonite before fermentation instead of after. Was that a bad decision?
- Cold fermentation yeast. The yeast is already some years old. But as it was unopened and smelt normally I still used it. It also started to ferment withtin a few hours. Could it still be that it was already expired?
- Yeast food: Same as above.
- Stabivit: After the fermentation I added 0,05% of the stabilizing agent "Stabivit", consisting of potassium disulphite, potassium sorbate and ascorbic acid.

As a wrapup: I don't suspect any of these agents to have spoilt the wine, but if, then I would suspect the early use of Bentonite or the old yeast. What do you think?

This is what I did so far:
Wine1 is already bottled so I didn't do anything yet. As wine2 is still in the make, I started with that one.
I did some tests with agents I had in my collection: gelatine, tannine, kieselsol, bentonite and the enzyme "zymex"
Link: https://www.brouwland.com/en/our-pr...vinoferm/d/enzyme-vinoferm-zymex-aroma-100-gr

I found out that "Zymex" and Benonite would make the wine a bit clearer and brighter, while the others wouldn't do a thing, so I used both of them: First Zymex, then I waited over night, then I added bentonite, waited for a day, and then I removed the wine from the sediment. Even though these agents had a visible effect on small samples I tested beforehand, the wine just looked eaxctly the same after their use. Now I added the stabilizing agent "stabivit", as described above, and put the wine in the refrigerator, to let some tartaric acid fall out. Let's see how it develops...