EngineJoe
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This is REALLY dorky... I'm guessing this won't be of much interest to anyone but me. But sharing knowledge/experience is always a good thing, so...
As a person who -- historically speaking -- brews beer, I don't have much experience with long aging, except in rare circumstances. And when I do, I usually do it in a 5 gallon stainless steel keg, sealed under CO2 pressure.
As a result, headspace hasn't really been a concern for me, except making sure I have enough in the primary. Minimizing hasn't really been my concern.
Well, now it is! Yesterday, I racked my first wine from the primary bucket to a 6 gallon Better Bottle for the stabilization/clarification stage. And I had to do some topping off to get the wine up to the old 'fill to 2" below the stopper' mark. So I opened up a bottle of wine and poured gently. It ended up taking nearly the whole bottle to get there! That got me wondering: is the 6 gallon BB really 6 gallons? Is the graduated primary bucket even remotely accurate? What about a glass 23L/6gal carboy?
The results were surprising.
Short version:
- where my bucket is marked 23L is actually just about 24L.
- a 6 gallon Better Bottle is actually 23.75L to the neck.
- a 6 gallon/23L glass carboy is actually 24.75L (about 6.5 gallons) to the neck.
These results obviously impact decisions on topping off vs. starting with more volume to start, etc.
Long Version/Method (for those who care) :
CALIBRATION: a US pint is 1 lb. To make sure my 32oz. measuring cup (it also measures mL) was accurate, I used my kitchen scale to weigh it out -- 32 volumetric ounces of water should weigh (drum roll) 32 oz. by weight. As it turns out, 32 fl. oz. on the measuring cup weighed 32.4 oz. Reasonably accurate for measuring out 6 gallons (only 9.6 oz. off out of 768 oz. -- a 1.25% variance). And as it turns out, that inaccuracy slightly mitigated the discrepancies in my results, not exacerbated them.
I measured out 1 gallon of water into a tall, thin pitcher (more accurate than short/fat) using the 32 oz measuring cup, then marked the gallon line. Using that, I added a total of 6 gallons to my primary bucket. Lo and behold, it came up to the 22L marker on the bucket. I added another 32 oz. and that brought it up to just about the 23L mark (which makes sense). LESSON: never assume your premarked/graduated gear is accurate.
Then I siphoned the water from the bucket to my 6 gallon Better Bottle. After the racking took all it could, I poured the remnants into my 32 oz. measuring cup. Result -- the Better Bottle was not full to the neck, and there was about 1L of water left behind in the bucket. I poured the water from the measuring cup to the BB and stopped when the BB was filled to the neck. I was left with about 250mL of water in the measuring cup. LESSON: So there is 23.75L capacity in a so-called 6 gallon Better Bottle (about 6.25 US gallons). (Aside: I had - anecdotally - had a similar experience with a 5 gallon BB when racking 5 gallons of cider from primary. I had to add about 3 12oz. bottles of my prior year's cider to get it filled to the neck)
I siphoned all of that water to the 23L glass carboy. Afterwards there was still a decent amount of headspace in the glass. I ended up adding a little more than 1L of water to bring it to the neck. Lesson: So there is actually around 24.75L capacity in the glass carboy.
To complete the circle, I siphoned from the glass carboy to my graduated bucket. After doing so, the water was slightly below the 24L mark on the bucket, again confirming that the bucket graduation was off by about 1L.
Conclusions: even if the measuring cup is not accurate, there is a significant discrepancy amongst the vessels (esp. the glass carboy). Thus, to ensure that your aging carboys are filled to the neck, the kit maker either needs to sacrifice gravity points (about 4.4% by my math) by adding about 1L more water at the start than is technically accurate... or they need to be willing to add a substantial amount of other finished wine at the secondary phase. Because if you actually start with 23L of juice, concentrate and water, you'll end up with maybe 22.85L in the aging carboy (I'm assuming some loss when racking off the lees). So that's a liter of headspace in a BB or two liters in a glass carboy that needs topping off.
Whether they'd rather lose a little gravity in the must upfront or top off with nearly a bottle (or more) of some other wine later, is up to the winemaker. In my case, I (inadvertently) started with 24L of fermenting must. I was able to transfer just over 23L of it to the BB, then had to top off with about 625mL of wine. I guess the upside was that I got a glass of wine out of it...
Comments? See holes in my logic/tests? Anyone still there?
As a person who -- historically speaking -- brews beer, I don't have much experience with long aging, except in rare circumstances. And when I do, I usually do it in a 5 gallon stainless steel keg, sealed under CO2 pressure.
As a result, headspace hasn't really been a concern for me, except making sure I have enough in the primary. Minimizing hasn't really been my concern.
Well, now it is! Yesterday, I racked my first wine from the primary bucket to a 6 gallon Better Bottle for the stabilization/clarification stage. And I had to do some topping off to get the wine up to the old 'fill to 2" below the stopper' mark. So I opened up a bottle of wine and poured gently. It ended up taking nearly the whole bottle to get there! That got me wondering: is the 6 gallon BB really 6 gallons? Is the graduated primary bucket even remotely accurate? What about a glass 23L/6gal carboy?
The results were surprising.
Short version:
- where my bucket is marked 23L is actually just about 24L.
- a 6 gallon Better Bottle is actually 23.75L to the neck.
- a 6 gallon/23L glass carboy is actually 24.75L (about 6.5 gallons) to the neck.
These results obviously impact decisions on topping off vs. starting with more volume to start, etc.
Long Version/Method (for those who care) :
CALIBRATION: a US pint is 1 lb. To make sure my 32oz. measuring cup (it also measures mL) was accurate, I used my kitchen scale to weigh it out -- 32 volumetric ounces of water should weigh (drum roll) 32 oz. by weight. As it turns out, 32 fl. oz. on the measuring cup weighed 32.4 oz. Reasonably accurate for measuring out 6 gallons (only 9.6 oz. off out of 768 oz. -- a 1.25% variance). And as it turns out, that inaccuracy slightly mitigated the discrepancies in my results, not exacerbated them.
I measured out 1 gallon of water into a tall, thin pitcher (more accurate than short/fat) using the 32 oz measuring cup, then marked the gallon line. Using that, I added a total of 6 gallons to my primary bucket. Lo and behold, it came up to the 22L marker on the bucket. I added another 32 oz. and that brought it up to just about the 23L mark (which makes sense). LESSON: never assume your premarked/graduated gear is accurate.
Then I siphoned the water from the bucket to my 6 gallon Better Bottle. After the racking took all it could, I poured the remnants into my 32 oz. measuring cup. Result -- the Better Bottle was not full to the neck, and there was about 1L of water left behind in the bucket. I poured the water from the measuring cup to the BB and stopped when the BB was filled to the neck. I was left with about 250mL of water in the measuring cup. LESSON: So there is 23.75L capacity in a so-called 6 gallon Better Bottle (about 6.25 US gallons). (Aside: I had - anecdotally - had a similar experience with a 5 gallon BB when racking 5 gallons of cider from primary. I had to add about 3 12oz. bottles of my prior year's cider to get it filled to the neck)
I siphoned all of that water to the 23L glass carboy. Afterwards there was still a decent amount of headspace in the glass. I ended up adding a little more than 1L of water to bring it to the neck. Lesson: So there is actually around 24.75L capacity in the glass carboy.
To complete the circle, I siphoned from the glass carboy to my graduated bucket. After doing so, the water was slightly below the 24L mark on the bucket, again confirming that the bucket graduation was off by about 1L.
Conclusions: even if the measuring cup is not accurate, there is a significant discrepancy amongst the vessels (esp. the glass carboy). Thus, to ensure that your aging carboys are filled to the neck, the kit maker either needs to sacrifice gravity points (about 4.4% by my math) by adding about 1L more water at the start than is technically accurate... or they need to be willing to add a substantial amount of other finished wine at the secondary phase. Because if you actually start with 23L of juice, concentrate and water, you'll end up with maybe 22.85L in the aging carboy (I'm assuming some loss when racking off the lees). So that's a liter of headspace in a BB or two liters in a glass carboy that needs topping off.
Whether they'd rather lose a little gravity in the must upfront or top off with nearly a bottle (or more) of some other wine later, is up to the winemaker. In my case, I (inadvertently) started with 24L of fermenting must. I was able to transfer just over 23L of it to the BB, then had to top off with about 625mL of wine. I guess the upside was that I got a glass of wine out of it...
Comments? See holes in my logic/tests? Anyone still there?