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Nothing too new here, but I had the following image to share. Let's say I have two identical planks of wood, that I happened to have hewn from an oak tree in the the Zemplen forest. I tie rocks to them (to make them sink); I throw one into the local high school swimming pool, and I throw the other into a baby wading pool. Do you think they would become "neutral" at the same time, or at different times? What is your reasoning?

It's early so I might not be thinking clearly through this, but if both are fully submerged then both would be exposed to the same surface area to liquid. I say neutral at the same time.

Now keep in mind, the HS swimming pool is likely to be more chlorinated and have a deep end with more pressure and the wading pool likely to have more urine in it, but they should have minimum affects on the planks going neutral.
 
It has to do more with what @Ajmassa5983 said in an earlier post. It's the number of batches that's getting you to neutral not time.

With the small volume barrel you reach your theoretical 35 units faster due to dilution to volume.

If you had a small barrel and a large barrel side by side and change out the wine when you hit your target dilution/units, but only refill the barrels with wine at the same time, they would more likely go neutral at the same time. But because the smaller barrel gets to the unit level quicker you are going to have new wine refills in shorter increments than the larger barrel, resulting it going neutral sooner.

If I'm understanding correctly the small barrel would sit empty until the larger reached the target extraction. In that case I agree the time to neutral would be the same.
 
If I'm understanding correctly the small barrel would sit empty until the larger reached the target extraction. In that case I agree the time to neutral would be the same.
Yes you understand correctly, but the last batch in the small barrel would still finish quicker than the last batch in the larger barrel, so the smaller barrel would go neutral faster.
 
It's early so I might not be thinking clearly through this, but if both are fully submerged then both would be exposed to the same surface area to liquid. I say neutral at the same time.

Now keep in mind, the HS swimming pool is likely to be more chlorinated and have a deep end with more pressure and the wading pool likely to have more urine in it, but they should have minimum affects on the planks going neutral.

Not to mention the surface to volume ratio will be a lot closer and you might have to take the temperature of the water into consideration. Plus the urine to water ratio!!!!!
 
OK let's start here using round numbers and assumptions:
200 liter barrel has 6500 sq. in.
20 liter barrel has 1400 sq. in.
Assume the number of units of potential oak extration is equal to the number of sq. in.
The potential number of units of extraction per barrel for a 200 liter barrel is 6500/200 or 32.50 unit/gallon
The potential number of units of extraction per barrel for a 20 liter barrel is 1400/20 or 70.00 units/gallon
So for the sake of simplicity let's call 35 and 70 half or double depending on how you look at it.
Now when removing the wine from the smaller barrel once it reaches the 35 unit extraction level you only have 35 units left.
If the rate of extraction is a constant the timeframe for the extraction takes half the time for a smaller barrel. Thus becoming neutral sooner.

Boy I can't wait to see the responses. LOL

PS, @sour_grapes I'm still thinking about you pool scenario. Don't have anything yet.

I really like the way you set this up.

Let me use your assumptions, namely, "if the rate of extraction is a constant." (It is probably more complicated, but let's use that for now.) The rate of extraction per area will be constant. Therefore, as @pgentile said, you will get your desired concentration faster. In your example, it would take exactly 1/2 the time as for the large barrel (and, as you say, you will have used up 1/2 of the small barrel's oak essence, or 35 units). Then you swap out the wine for a new batch in the small barrel, but leave the big barrel sitting. Now, you will extract the remaining 35 units of the small barrel. This again takes 1/2 of the time as the whole process takes for the large barrel. Therefore, they both become neutral at the same time.

Of course, we know the rate of extraction is not really constant. I am going to make another post discussing that, but I haven't reached a conclusion.
 
I really like the way you set this up.

Let me use your assumptions, namely, "if the rate of extraction is a constant." (It is probably more complicated, but let's use that for now.) The rate of extraction per area will be constant. Therefore, as @pgentile said, you will get your desired concentration faster. In your example, it would take exactly 1/2 the time as for the large barrel (and, as you say, you will have used up 1/2 of the small barrel's oak essence, or 35 units). Then you swap out the wine for a new batch in the small barrel, but leave the big barrel sitting. Now, you will extract the remaining 35 units of the small barrel. This again takes 1/2 of the time as the whole process takes for the large barrel. Therefore, they both become neutral at the same time.

Of course, we know the rate of extraction is not really constant. I am going to make another post discussing that, but I haven't reached a conclusion.

Wating anxiously. Unfortunately I have to go to my boat to change the bilge pumps so it doesn't sink. LOL but not really.
 
Well, I have looked at this a number of times/ways, and just don't see any explanation for a shorter time for smaller barrels to become neutral.

I tried two more things today (again, on the theoretical front). Because the oak essence will come out fast at first, and then more slowly after some of it is used up, I tried a simple model where the rate of extraction varies with time t. (I chose it to be proportional to exp(-t/T) because that is easy to handle mathematically.) I found, as expected, that for the smaller barrel, the time to oak-up the first batch was smaller than the time to oak-up the second. But the sum of those times is exactly the same as the time to oak-up the larger batch that has half the Area/Volume ratio.

Next, I recognized that the math of diffusion is rather well-known. It is well-described by Fick's Law; by "well-described," I mean there is a mechanistic, molecular-level theory of diffusion that leads to a fairly simple mathematical result. When we compare the predictions of Fick's Law to actual experiments, across a wide, wide range of phenomena, you get very good agreement. The "mathematical result" I cited above is a differential equation, but you have to solve it for the situation at hand; for example, it can describe both, say, dumping a load of dye into a lake, or, say, drying wood in a kiln, but you need different solutions to that differential equation to reflect those different initial conditions.

These expressions are kinda complicated. Just for example, I was playing around with expressions like these (for the concentration c of oak essence left in the wood as a function of depth x and time t):

diffusion.jpg


where erf() is a complicated but well-known mathematical function.

But the thing is there is very little in these exercises to distinguish large barrels from small ones.** Like the planks in the two swimming pools, the extraction of oaky goodness from the wood just goes how it goes, not "knowing" if it is diffusing into a large volume or a small one. It became clear to me as I was playing with this that there was not even a way to encapsulate the information about the size of the barrel (except as described in ** below). I am forced to conclude that barrels of all sizes become neutral at the same rate.


** There is one, minor effect that differs between the case of large and small barrels, namely, the concentration of oak in the wine increases faster for the small barrel, and thus could possibly slow down the continued outdiffusion of oak essence from the wood. However, this is problematic for two reasons. First, it should be a very small effect, because the concentration of the oak flavors in the wine is many orders of magnitude smaller than in the wood. Moreover, this effect works the wrong way: if taken seriously, it would indicate that small barrels should take longer to attain neutrality.
 
I'm going to leave this one go for now. What is experimentally known is smaller barrels do give off oak faster and they go neutral around 18 months. There has to be something not being taken into consideration.

I don't even own a barrel yet and this is bothering me now for two days.

@sour_grapes very impressive, but once I got to the square roots in your calculation my brain fried, it's been way to long since high school and college.

Did some research(Googles) and there is not much information on barrel size and any type of analysis tangible to our subject here.

But it appears that the unknown element in this could be micro-oxygenation rates on the size of the barrel's surface area to volume, not just what leeches out of the wood for the same reason.

Like I said not much out there but here are a few links:

"When people discuss cooperage, they often focus upon wood. But oxygen also informs aging. Take the surface area to volume ratios above and add another factor—not the barrel itself, but the air resident in it. Oxygen is a serious contributor to a wine’s evolution. Small amounts of oxygen pass through the barrel, the joints, and the bunghole. If you use a larger barrel, like the Foudre, the wine receives proportionately less oxygen than it would if it were casked in a barrique or a puncheon, since there is a lower ratio of surface area to wine volume."

https://pisoninotes.com/notes/barrel-sizes-matters-lucia-chardonnay/

"Smaller barrels have a stronger impact on wine, so most Brunello producers use botti because they feel three years aging in small casks would produce overpowering oak flavors in the finished product."

http://winesnark.com/when-it-comes-to-wood-size-does-matter/

Still reading stuff so it's just a hypothesis at this point. I'm reading about some old world wineries switching from giant casks to smaller barrels because of faster maturation.
 
I’ll agree that the concentration of oak flavor accumulates in a wine that’s in a small barrel at a faster rate than a larger one, and believe most all agree that this is the case. Presumably, this is due to the ratio of wine volume to exposed wood area, and I think most understand and agree.

When it comes to longevity, I’m with @sour_grapes, and believe that neutrality (inability to impart detectable oak flavor) is consistent in barrels of various sizes made of the same wood. My 12 gallon barrel lasted no longer than my 6’s, though the 6 will oak more wine than the 12 due to the ratio mentioned above. The wine I have in a brand spanking new 30 gallon barrel still shows little to no oak flavor 9 months into its gig, whereas 6 gallons would have been ruined (overoaked) in a new 6 gallon barrel by now. IMHO, soak time determines how long a barrel lasts before neutrality, independent of the ratio.
 
Well, I have looked at this a number of times/ways, and just don't see any explanation for a shorter time for smaller barrels to become neutral.

I tried two more things today (again, on the theoretical front). Because the oak essence will come out fast at first, and then more slowly after some of it is used up, I tried a simple model where the rate of extraction varies with time t. (I chose it to be proportional to exp(-t/T) because that is easy to handle mathematically.) I found, as expected, that for the smaller barrel, the time to oak-up the first batch was smaller than the time to oak-up the second. But the sum of those times is exactly the same as the time to oak-up the larger batch that has half the Area/Volume ratio.

Next, I recognized that the math of diffusion is rather well-known. It is well-described by Fick's Law; by "well-described," I mean there is a mechanistic, molecular-level theory of diffusion that leads to a fairly simple mathematical result. When we compare the predictions of Fick's Law to actual experiments, across a wide, wide range of phenomena, you get very good agreement. The "mathematical result" I cited above is a differential equation, but you have to solve it for the situation at hand; for example, it can describe both, say, dumping a load of dye into a lake, or, say, drying wood in a kiln, but you need different solutions to that differential equation to reflect those different initial conditions.

These expressions are kinda complicated. Just for example, I was playing around with expressions like these (for the concentration c of oak essence left in the wood as a function of depth x and time t):

View attachment 49776


where erf() is a complicated but well-known mathematical function.

But the thing is there is very little in these exercises to distinguish large barrels from small ones.** Like the planks in the two swimming pools, the extraction of oaky goodness from the wood just goes how it goes, not "knowing" if it is diffusing into a large volume or a small one. It became clear to me as I was playing with this that there was not even a way to encapsulate the information about the size of the barrel (except as described in ** below). I am forced to conclude that barrels of all sizes become neutral at the same rate.


** There is one, minor effect that differs between the case of large and small barrels, namely, the concentration of oak in the wine increases faster for the small barrel, and thus could possibly slow down the continued outdiffusion of oak essence from the wood. However, this is problematic for two reasons. First, it should be a very small effect, because the concentration of the oak flavors in the wine is many orders of magnitude smaller than in the wood. Moreover, this effect works the wrong way: if taken seriously, it would indicate that small barrels should take longer to attain neutrality.

YES! This response did not disappoint!! With Fick’s Law to boot! I looked at it from a couple angles myself, and also kept proving the opposite somehow too.
The experiment I kept re-visiting was to take (x2) 60 gal barrels- one filled with 60gal. The other filled with 30gal and a 30gal bladder inserted. And down the wormhole I went. Results were interrupted when the plank was removed from the pool and used to beat a dead horse unfortunately.
 
Thanks, all, for the nice discussion. I apologize for my role in the threadjack, but since it was Fred's thread to begin with, at least I am in good company! I am kinda glad this discussion took place in a thread about a Mid-Atlantic meet-up, because I think we were "overlooked" by some other contributors who normally would have chimed in! ;)

@Johnd, thanks for your comments. I must admit that I misunderstood your post the other day. I thought you were saying that small barrels did become neutral faster, and I took your claim (which I misunderstood) very seriously. I should have spent more time on reading comprehension than on Fick's Law! :D
 
@Johnd, thanks for your comments. I must admit that I misunderstood your post the other day. I thought you were saying that small barrels did become neutral faster, and I took your claim (which I misunderstood) very seriously. I should have spent more time on reading comprehension than on Fick's Law! :D

LOL!! I didn’t know you were debating with me, we’re on the same track on this one!!

The only variable that I can envision, you mentioned, is one of “saturation”. Can wine get enough oak in it such that it can’t take any more, and if so, as the saturation level increases, does the amount of oakiness extracted from the barrel decrease, leaving more for the next wine? Or is it simply a straight line depletion based on time and independent of wine volume or oakiness? I tend to think the latter, with no data to back it up, only gut......
 
Sometime this week I going to reserve the rooms at Split Rock. I think I'll start with 10 like last year. I'll reserve them at the Lodge and try to get us on the same side of the second floor. Let me know if you are planning on cominng. The 6 of us such a great time I can't imagine what 10 or more would be like. I'm going to post this on the other thread to make such those interested see it. Also, if you want the main facility or a cabin please let me know and for those of you that didn't come last year there is a 2 night minimum.

https://www.splitrockresort.com/things-to-do/events/wine-festival/
 

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