You can read the full report of the study here.
Final Report on my 24-Month Comparative Study on the Evolution of Wine Aged in a Flextank vs. a Second-Year Oak Barrel
Techniques in Home Winemaking
A blog for those passionate about home winemaking
You can read the full report of the study here.
Hi Daniel,
I appreciate your study, and your book!
I am wondering if you have tested or have thoughts about the heavyweight version of Flex Tank with reduced oxygen transfer rate? I am thinking that, given the relatively high surface area to volume of a small tank such as the 15 gallon ECO, perhaps the thicker version would be best for bulk aging?
I am also wondering if you find that you can rack by gravity off of settled fine lees using the spigot, or is it placed too low for this? My understanding from calling Flex Tank is that their rotating racking arm accessory is too large for the 15 gallon tank.
Hi Ken,
No, I have not worked or tested the heavyweight version of Flextanks, but yes, you will get slower oxygen transfer into the tank and wine. The choice of type really depends on your aging regimen and duration. The light-weight tanks require monthly FSO2 checks and adjustments, just like a barrel.
Yeah! I don’t know why they don’t make a racking arm that fits the 15-gal ECO. It’s easy enough to cut though, or you can purchase one, a better one with a much nicer finish. I have several that I bought from a supplier here in Canada. I always use the racking arm.
Daniel
Thanks Daniel.
I currently have 15 gallons of Mencia, 15+ gallons of Pinot Noir, and close to 15 gallons of Albariño in the midst of fermentation, all from beautiful Columbia Gorge grapes. I really don’t want 9 more 5 gallon glass carboys!
I do have four 7.5 gallon Anvil stainless steel fermenters that I use for whites and roses (they do come with racking arms!), haven’t known of these being potentially also used between harvests for a bulk aging year and not sure they are sufficiently air-tight…
Do you have a link for the racking arms that you mentioned ? I also have the same issue with the plastic 60L Speidel fermenter I have.
Here is the link. This is a good-quality racking arm. Keep in mind that I’m in Canada; this is a Canadian vendor, and prices are in $CAD. I don’t know if he ships to the US but I don’t see why not.
https://www.ontariobeerkegs.com/tc-rotating-racking-arm.html
Thanks, I ordered the Flextanks, valve flange kits, and 1.5” TC racking arms very similar or same as your example. I am new to the Tri-Clover fittings system and am wondering if you favor a butterfly vs ball valve? I will be attaching a hose barb and racking by gravity.
It makes no real difference if you are just moving wine, but when working with must (i.e. wine and grape solids) and doing pumpovers, I find butterfly valves to be a pain as they tend to clog fairly easily with 1.5″ fittings.
I have wine in the tanks now, am very much unclear about how to minimize headspace and unwanted oxygen ingress at the top. How to measure or judge how tight the lid is screwed down and what “suitable” wrench did you find for this? Where do you fill to?
My biggest concern is the threaded port in the cap for the supplied bung and wet airlock, a problem you point out. No threaded airlock was provided, the solid imported green cap was but I feel uncomfortable using a solid cap rather than an airlock. Any update thoughts on these practical issues with the tanks in use?
Fill into the new right to the top, just a tab below the lid so that when you install the lid, the wine does not overflow. Tighten lid as hard as you can; I also apply a dab of EVOO, but be forewarned, you’ll need a strap wrench to unscrew. You will need to purchase a threaded-port cap for use until the wine has outgassed sufficiently. To install a wet airlock on a threaded-port cap, you can simply connect a plastic or stainless steel NPT-threaded cylindrical adapter and then insert a bung/airlock.
I meant to write fill into the neck right to the top.
Daniel, we have filled as high as seems possible, have applied olive oil to the gaskets, tightened the large main lid by hits to its flanges with a rubber hammer, Teflon-taped the threads of the 2” NPT green cap and of a 3/4” NPT hex nipple in the port of that green cap to give an unthreaded seat for a bung. But I still cannot achieve uneven Vodka levels in the S-type airlocks.
Is this just the way it is no matter what with a tank with some structural flex (Flextank ECO 15s), or evidence that there is an air leak that if not solved dooms the circa $4500 of wine to failure by way of oxidation and volatile acidity? A critical decision point! I do really want aging in these tanks to succeed! Thanks for your experience-based insight.
The lack of uneven airlock fill levels is not a conclusive sign that there is an air leak, that the lid is not sealed properly. Assuming that the wine has degassed and is causing no effect in the airlock, if there is no headspace whatsoever, you may or may not see any positive pressure in the airlock upon insertion. If you’re not displacing any air, you won’t see anything in the airlock. It also depends how you insert the stopper/airlock. You are likely ok, but as a check, you should measure FSO2 once a month, and if you see any larger than expected drop, then you likely have a problem. Also check for any VA or acetaldehyde, and/or surface film — those would be indicators of air ingress.
Daniel