FlexTank instead of oak barrel...really interesting

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I think flextanks are great and they definitley have a purpose in the winery, esp with white wines. But they can in no way replace a barrel for a red wine!
From the flextank website:

The “Angels Share” is retained – no losses and no routine topping required.

That right there tells you you have NO micro-oxidation going on as well as NO Concentration through evaporation via the loss to the Angels.

That said you can buy (a very expensive) Micro-oxidation delivery system to add on you a flextank but you still wont have the concentration effect.
 
Mike the tanks do allow for micro-oxidation, but not concentration. According to their website:

How does oxygen get into the wine?
The tank itself is permeable to oxygen. The actual permeability required is engineered by attention to resin selection and blend, surface area to volume ratio and wall thickness. The maturation range of Flextanks is designed to have a similar oxygen permeation rate to the typical second year wine barrel when used at a nominal cellar temperature of 55F. Oxygen is driven across the tank wall by the partial pressure differential between the wine and the atmosphere. Upon permeating into the wine the oxygen is used up by the complex chemical changes that occur during maturation.

I have seen somewhere online a chart comparing the oxygen permeability, but short of looking it up right now I don't have it at hand.
OK here it is

Oxygenation%20Graph.jpg
 
I was just reading that on their website. That is one heck of a claim……. That Polyethylene or Polypropylene whichever they are using has the same permeability as a wooden oak barrel.

If that is true then SO2 levels would be dropping like a rock when you use them just as they do with a barrel.

Is that what you see Rich? How does your SO2 levels hold up in a Flextank?
 
So you get the oxygenation of a barrel but not the concentration. Both seem important to me as a home winemaker but a commercial winery making bulk wine would love to keep the angel share for themselves.
 
I still am not convinced they will oxidize at the same rate as a barrel. Need to see a comparative study! LOL I do know you can install an OxBox
 
The S02 levels just need monitoring periodically and replacing as need be. It is just a maintenance operation. I find with my use it isn't much different than any other storage, but then the pH tends to be lower than with vinifera grapes.
 
If that is true then SO2 levels would be dropping like a rock when you use them just as they do with a barrel.

According to the studies on this page (http://www.flextank.com.au/trials-aus.htm), SO2 levels in flex tanks drop at the same rate as oak barrels.

A 2006 Shiraz, after malo-lactic fermentation, was added to the following vessels:

3 x new American oak hogsheads
2 x 1000 Litre Flextanks, each containing one 'Flextank 8 QP' modular oak stave pack
3 x 2100 Litre Flextanks, each containing two 'Flextank 8 QP' modular oak stave packs

All vessels were kept in the same storage area (same temperature and humidity) for the eleven months duration of the trial. The intention of the trial was to monitor relative changes in various chemical parameters for the wines stored in the different vessels.


SO2%20Graph%20Fig.%202.jpg


Free sulfur dioxide concentration (mg/litre) in 2100 litre Flextanks (BP01, BP02, BP03), 1000 litre Flextanks (BP05, BP06)
and new American oak hogsheads over 5 months.

The free sulfur dioxide concentrations were essentially the same in all storage vessels after the 11 month maturation period. Importantly, the rate of free sulfur dioxide loss in the first five months occurred at the same rate for the oak and Flextank vessels, showing the validity of Flextank's oxygen permeation physics and vessel designs.
There was no significant difference in wine colour density after 11 months, while the wine hue was higher in the Flextank vessels in comparison to the oak vessels. Levels of oak volatiles increased during the time course of the maturation study, irrespective of storage vessel type.
The concentrations of free dimethyl sulfide in the Flextank vessels were slightly, but not significantly, higher than in the oak vessels (8 to 10 microgram/litre compared to 6 microgram/litre). The measured concentrations of hydrogen sulfide were the same in all vessels and the levels of methanethiol were below detection.
 
It would be nice to see an unbiased study done by someone other than the manufacturer making the claim.
 
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Do you really want to keep the "Angels Share"?
You need to think about this. I have a flex tank. I bought it based on the projected life. Barrels are expensive and difficult to clean. I still think a flex tank is the best option, but not because you keep the angels share.
As it happens I have a borrowed 220 litre barrel filled with water. (Made a lot of port and didn't need to use it again last year) It sat next to the flex tank all year and took about a gallon of water (with k-meta) top up per month.
This made me start thinking. The flex tank lost nothing.

The bung was firmly in place. The only way for the volume to change in the barrel was through the wood. If that is the case then surely molecular size is going to be significant. Of what is in the wine, the smallest molecules are CO2 and H2O.

To me, this means that the wooden barrel is actually increasing the concentration of the wine. Improving the flavour.

If you make kit wines this would be like reducing the amount of water you add.

If you use grapes, this is possibly the only way to remove water without affecting the flavour of the wine negatively. Certainly, the easiest.

I am happy with my flex tank, but there is a place for barrels. Just make your decisions for the right reasons.
 
Of course concentration in a barrel is a factor to consider. It does affect the wine and is often desirable.

I'm wondering how well flex tanks work for holding white wines vs steel for, say, 6 months or so? Is it people's experience that the oxygenation is good or detrimental?
 
In 2012 I did a side by side with my flex tank with staves in it and a one year old barrel and compared with a carbou of the same wine and aged them for a year.

Yes the free so2 levels dropped at more or less the same as the barrel .

The micro ox effect of the flex tank is noticeable , the wine is smoother and tannins more integrated compared to the carboy.

Compared to the barrel the wine is a bit brighter and more fruit forward.
But in a nice way.
In a blind tasting 4 out of 9 preferred the flex tank .

2 people couldn't tell the difference , me I preferred the barrel but was very impressed with the ft.

This was a Bordeaux blend . But if I was making zin ,Pinot or sirah , I'd probably flex tank it to keep the brighter fruit and light aromatics .


You don't always want any concentration effect , especially if you had any grape raisining / grape dehydration to start with , the preservation of the brighter fruit flavours and lack of concentration effect would be highly desirable in a crazy hot dry year.

For a white wine six months is good , if you need to go longer get the thicker tank. I like the flex tank for six months , it gives the wine a bit more mouthfeel and takes the acid edge off ( doesn't actualy reduce acid but reduces the nails on chalkboard brightness) Great for Chardonnay Viognier or high acid hybrids especially if combining with surlie (natural or biolees) . For Gewurtztraminer, Riesling or Pinot Gris , I'd stick with steel or the thicker tank.
 
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I blended them together , the barrel, tank and carboy before bottling which worked out well.

I did bottle a case of each before blending to see how it develops individually as comparison to the main batch ( 45 cases)
 
I am liking this even more....but it looks like the smallest vessel is 30 gallons.
I imagine someone needs to make about 32 gallons of wine and when all set and done after fermentation and racking end up with ~30 gallons to age and keep the container full.
 
All the data you guys are showing has been provided by the FLEXTANK manufacturer! Of course it is written that way....... What else would they say!!!! The only data to consider was Altavino since his was un bios.... But still showed no great benefit over a barrel.


Sam
 
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All the data you guys are showing has been provided by the FLEXTANK manufacturer! Of course it is written that way....... What else would they say!!!! The only data to consider was Altavino since his was un bios.... But still showed no great benefit over a barrel.


Sam

By benefit, you mean in the qualities of the wine? All things being the same and the wine turning out with the same quality, there are great benefits in terms of cost, cleaning and maintenance of flex tanks over barrels.
 
By benefit, you mean in the qualities of the wine? All things being the same and the wine turning out with the same quality, there are great benefits in terms of cost, cleaning and maintenance of flex tanks over barrels.

Absolutely! My only concern is that there is any validity to their claim..... The only real data the end users have of this product is what was given to us from the manufacturer themselves! Breathable plastic is a hard pill to swallow. I would need to see some evaluation data from a third party before I could support their theory on this happening...... Not the CEO of the company making a statement on it! There are millions of diet pills on the market too..... None will help you loose weight for any period of time as promised!
 
You guys need to get out more .

Flex tanks have been independently tested in both the wine trade magazines . Wbm & w&v .

Most of the research came from early negative experience with oxidisation in plastic containers , changing the formulation and wall thickness allowed the dialling in of permeability rates upto and including exclusion. There is nothing complicated about it , basic polymer chemistry .

These have been used commercially for over 10 years and there use is becoming increasingly common, 1000 wineries in the USA alone according to w&v magazine . Commercial makers wouldn't risk hundreds of thousands of dollars if they didn't work.

If you don't believe oxygen can permeate plastic , take a finished carboy of wine , rack it into a plastic water jug like those used for office water coolers , fill it right up and put a solid bung in and seal it with wax .
Wait 6 months , then cry over your oxidized wine.
 
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