Cold Expansion? Very confusing…

[crushday]

I have been noticing how stored wine seems to be expanding as colder weather creeps in. Case in point: I have a 100L Speidel storage tank that appears to be filing the airlock which I have installed as the wine is degassing. During the warmest weather this summer, the level of the wine didn’t increase noticeably. You can see from the pictures, that is no longer the case. You can also see from the pictures that it’s quite cold.

Does anyone have an explanation for this? Filtered through my limited knowledge of physics, it makes no sense to me.

Notice the red laser dot on the storage tank and the temperature:




Notice how the wine has expanded and has filled the large Speidel airlock…

 

[Jim Welch]

Different compounds and elements have different coefficients of expansion (and therfore contraction) due to temperature change, could be the vessel is contracting more than the wine itself and the effective volume is decreasing but that's just a guess. They look like HDPE vessels from the pic, are they HDPE?
BTW, I think laser thermometers work best on non reflective surfaces and are less accurate on reflective surfaces. Not doubting the wine has cooled though.

 

[crushday]

Yes, the vessels are HDPE - the effect of cold on the vessel isn’t something I considered. I pulled 9oz from the vessel tonight.

The laser pointer temperature is on point with the wall thermometer in that same room.

Thanks for your help!

 

[ibglowin]

Normally the biggest factor we have to worry about is the expansion of wine (ethanol) with increased temps (reverse happens with cooler temps) which can pop a carboy stopper out of a glass carboy if there is not enough room and the pressure builds up. What you are seeing is pretty weird IMHO I don't have any of those Spiedel tanks but I do have two 15G Flextanks and they do not seem to exhibit the behavior you are seeing in the Spiedel tanks.

 

[sour_grapes]

Hang on, I am re-calculating!

Okay, on second thought, perhaps @Jim Welch nailed it. (I leave my "first thoughts" below, but I missed an important factor.)

Revised effort:
I never would have thought of the factor that @Jim Welch cited. It turns out that HDPE has an abnormally large coefficent of thermal expansion, and this may be enough to explain your situation.

The thermal expansion coefficient for HDPE is ~67E-6 in/(in*ºF). That means that, for a change in temperature, of, say, 30ºF, the walls would change in length by about 30ºF*67E-6 in/(in*ºF), i.e., they would shrink by about 0.002 (i.e., 0.2%). This would change the volume by about 0.006, i.e., 0.6% . For a 100L vessel, that means the vessel will shrink by 100L * 0.006 = 0.6 L, or 600 mL.

In the meantime, by a similar analysis, the volume of the wine would have shrunk by about 360 mL. So, net/net, there would be an excess of about 240 mL.

I think @Jim Welch may have cracked it!




Wow, that is weird! I do not know what is going on.

I never would have thought of the factor that @Jim Welch cited. And it turns out that HDPE has an abnormally large coefficent of thermal expansion. However, I do not think it is enough to explain your situation.

I claim that for a, say, 30ºF change in temperature, the walls of your vessel would shrink by about a factor of 1 part in 3xE-5 (i.e., 0.00003). This would change the volume by about 1 part in 9E-5, or let's just say 0.0001. For a 100L vessel, that means the vessel will shrink by 100L * 0.0001 = 0.01 L, or 10 mL. Ten mL of excess volume is not nothing, but I think you are seeing a lot more than that!

So I got nothing!

 

[crushday]

So, net/net, there would be an excess of bout 240 mL.

Since I removed 9oz, or 270 mL, that makes a ton of sense!

I love this forum!

 

[NorCal]

Hang on, I am re-calculating!

Okay, on second thought, perhaps @Jim Welch nailed it. (I leave my "first thoughts" below, but I missed an important factor.)

Revised effort:
I never would have thought of the factor that @Jim Welch cited. It turns out that HDPE has an abnormally large coefficent of thermal expansion, and this may be enough to explain your situation.

The thermal expansion coefficient for HDPE is ~67E-6 in/(in*ºF). That means that, for a change in temperature, of, say, 30ºF, the walls would change in length by about 30ºF*67E-6 in/(in*ºF), i.e., they would shrink by about 0.002 (i.e., 0.2%). This would change the volume by about 0.006, i.e., 0.6% . For a 100L vessel, that means the vessel will shrink by 100L * 0.006 = 0.6 L, or 600 mL.

In the meantime, by a similar analysis, the volume of the wine would have shrunk by about 360 mL. So, net/net, there would be an excess of about 240 mL.

I think @Jim Welch may have cracked it!




Wow, that is weird! I do not know what is going on.

I never would have thought of the factor that @Jim Welch cited. And it turns out that HDPE has an abnormally large coefficent of thermal expansion. However, I do not think it is enough to explain your situation.

I claim that for a, say, 30ºF change in temperature, the walls of your vessel would shrink by about a factor of 1 part in 3xE-5 (i.e., 0.00003). This would change the volume by about 1 part in 9E-5, or let's just say 0.0001. For a 100L vessel, that means the vessel will shrink by 100L * 0.0001 = 0.01 L, or 10 mL. Ten mL of excess volume is not nothing, but I think you are seeing a lot more than that!

So I got nothing!

Nicely done. Gotta love those that can apply science. Nice pick-up @Jim Welch

 

[Boatboy24]

Wow, good analysis. I was wondering if air pressure would have anything to do with it as well.

 

[balatonwine]

I have quite a few Speidel tanks, and yes they do expand and contract. But normally that is only an issue if they are over filled. I noted, for example, wine running down one barrel in the OP's photo. Probably over filled and the wine is above the gasket.

I know people get paranoid about O2, but if degassing is still going it will put CO2 in the head space, so no need to over fill. For the "screw" top Speidel tanks, half way up the neck is more than enough in most cases (in extreme temp changes, that may even be too much). You can top up after degassing. But still keep it well below the top of the gasket.

The cylindrical tanks with the clamp on lids actually have space in the lids that compensate, but the screw on ones not so much. So do not over fill. If you are really worried about O2, just get a Nitrogen tank and put some N down the air lock tube before adding the air lock cap.

Hope this helps.