Help please. Wine turns bitter after bottling.

[Pavel2012]

I would like to ask for opinion/advice regarding a problem I consistently have with my wine batches. Understandably, it is difficult to pinpoint a problem in a virtual environment, but any help is much appreciated.

All wine batches I made so far turn bitter shortly after bottling. I am reasonably sure that the bottling is an issue here, there must be something I am doing wrong, but so far anything I tried haven't helped much. I will give details about overall process later.

Within a month-two months time bottled wine turns bitter. This effects practically every bottle, but afterwards this problem develops differently bottle to bottle. Option 1. Bitter taste disappears after 3-4 months resulting in a reasonably good wine. Option 2. Bitter taste disappears after 3-4 months but the wine tastes as if it was aged well beyond shelf life and started to dye. Option 3. Bitter taste stays permanently. I tried bulk age wine for few months and then to bottle, the wine tastes fine after bulk aging but turns bitter after bottling.

Bottling details:
Bottles are rinsed with "Pink powder"(chlorinated phosphate) solution, water, KMETA solution, water.
Corks are soaked in KMETA solution for 1h, rinsed with water. I use standard cork press, haven't figured the way to sanitise the press yet.
All transfer lines are rinsed with pink powder and KMETA.
Process details:
Juice: Grape juice with added yeast (So far tried Red Cabernet, Cabernet Sauvignon, Alicante and Zinfandel).
Fermentation: 25L fermenter for 1 week, then two-three weeks in a glass carboy until specific gravity is OK.
Clarification: Kieselsol/Chitosan 1 week.
Stabilization: K-sorbate 0.1g/L + K-META (0.05g/L) added at clarification time.
Fine is filtered through a coarse filter on Micro-Jet before bottling.

Thank you for your help.

 

[Julie]

What sg is ok and why are you sorbating a wine that doesn't seem like you are backsweetening. The bitterness could very wellb e coming from the acid level, you need to check your acid. Also, understand each batch will be different. I really do not believe it is bottling that is causing your bitterness. It is the wine. Check you acid levels before you bottle

 

[Tess]

Could this be bottle shock??

 

[Pavel2012]

Julie, thank you.
I don't believe it is too much acid, the taste is different. Should get a pH meter at any rate. My understanding is that sorbate helps to preserve the wine apart from stopping fermentation. Good comment, sorbates are known to go through secondary reactions.

Tess, my understanding is that bottle sickness is something that typically happens withing a week or so and lingers for a few weeks. It is not the case, then, I had bottles that kept the bitterness for a year.

 

[Turock]

Since you are having problems in all your wines, there is something you are doing that seems to be a common element. So it's time to try a few things. I would lose the "pink powder" and use only meta solution for sanitizing. Do not rinse after soaking eqiupment in it. Chlorinated products should not be used, and certainly not for sanitizing.

Are you adding extra tannins to the wine and if so when are you adding them? Too much tannin can cause bitterness.

Do not use sorbate unless backsweetening and you should never sorbate a cloudy wine because it can't work properly until the bulk of the yeast cells are removed thru racking. Be sure to allow at least one year of bulk aging, on wines like these, before bottling. The wine will really firm up flavors in that time, and be clear.

You might want to try treating these bitter wines with Caseine. It is good for eliminating bitter compounds.

Most juice buckets today come with brix and acid adjusted and the yeast already in it so there's not much to do when working with them. So it seems that the wine is not the problem. I suspect it's something you're doing.

 

[MrKevin]

Pavel
After reading your post, I agree with Turock, Loose the pink powder, I researched chlorinated phosphate and it needs to be neutralized with citric acid, since this is a common denominator, this could very will be your problem.

 

[LoveTheWine]

Pavel
After reading your post, I agree with Turock, Loose the pink powder, I researched chlorinated phosphate and it needs to be neutralized with citric acid, since this is a common denominator, this could very will be your problem.

The pink powder is know as sani-brew or diversol and is used all the time as a disinfectant and sanitizer in beer and winemaking. It must
be rinsed thoroughly after use with clean water.

I use Sani-brew all the time to do a deep clean if equipment or bottles are actually dirty but usually use just K-meta solution to sanitize items that are already clean.


What kind of water are you using to rinse? Is it high in chlorine or iron?
This could impart a flavor to wine.

I agree with everyone, sorbating a dry wine is something not to do.

I would stop soaking your corks. Soaking them makes them fall apart. Insert them dry or use a humidor first. You can clean the corker with rubbing alcohol before use if it is unsanitary.

 

[Pavel2012]

Thank you for replies.

I agree, K-sorbate addition at clarification could be the issue.

I share concerns about chloro-phosphate ("pink powder"), but it is not the problem, I tried without it with similar results. The phosphate is basic and tend to linger around, but I typically do few water washes followed by KMETA wash. KMETA should take of any residual basicity and active chlorine.

Very interesting point about water. I do use tap water for rinses, it is chlorinated and has heavy iron content.

A bit confused about soaking corks. Presumably they need to be sanitised, they do not fall apart, I use solid cork, not composit. At the same time cork package come with a warning "Do not soak".

Pavel

 

[Turock]

Pavel---How long have you ever bulk aged any of these wines? Bulk aging will remove bitter components, given enough time.

You really don't need to soak the corks. The acids and alcohol content along with sulfite are far and away enough protection that any slight bacteria on the corks is not an issue. Some corkers don't like pushing a dry cork. So if it works better with them wet, go ahead and let them soak a bit for easier insertion.

 

[LoveTheWine]

Thank you for replies.

I agree, K-sorbate addition at clarification could be the issue.

I share concerns about chloro-phosphate ("pink powder"), but it is not the problem, I tried without it with similar results. The phosphate is basic and tend to linger around, but I typically do few water washes followed by KMETA wash. KMETA should take of any residual basicity and active chlorine.

Very interesting point about water. I do use tap water for rinses, it is chlorinated and has heavy iron content.

A bit confused about soaking corks. Presumably they need to be sanitised, they do not fall apart, I use solid cork, not composit. At the same time cork package come with a warning "Do not soak".

Pavel

I guess my experience with corks falling apart was when I boiled Amalgamated corks and later found them falling apart.
Real cork should hold up much better.
I would heed the warning on the package though.