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Measuring the volume of spirits


Williamsburg Distillery

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Hello everyone,

I have searched but couldn’t find a way to measure and keep a good record for TTB on the distilled spirits.

I would like to use volume instead of weight since I’m not making enough to justify a scale.

For tax and records, what type of container are you using to measure the spirits coming out of the still?

Does it have to have marked measurements on it for TTB inspection?

Or do I use the barrels and/or bottles for that purpose?

Cheers :)

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Thanks Matt, i know i read somewhere were you can keep track by volume.

What do most of you do to keep track of the spirits prior to bottling?

Does this fit the legal requirements for tax purposes measuring by volume once it leaves bond?

27CFR30.52
Procedure for measurement of cased spirits.
Where the quantity of spirits in a case is to be determined by volume, such determination shall be made by ascertaining the contents of one bottle in the case and multiplying that figure by the number of bottles in the case. For cases containing bottles filled according to the metric system of measure, the quantity determined shall be converted to wine gallons, as provided in § 19.722 of this chapter. The wine gallons of spirits thus determined for one case may then be multiplied by the number of cases containing spirits at the same proof when determining the quantity of spirits for more than one case. The proof gallons of spirits in cases shall be determined by multiplying the wine gallons by the proof (divided by 100).

Cheers,

Mike

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Volume measurements are very tricky and require some pretty intense math and conversions to make them work.

Volume constants are given under STP (Standard Temperature and Pressure), or under SATP (Standard Ambient Temp and Pressure). So your 1L of water is really only 1L at whatever constant was found. If it is warm outside and you are at 3,000ft elevation, you have 2 corrections to make to your water, and 2 corrections to make to your ethanol.

Every time you want to proof these calculations will have to be done again. This will also increase the margin of error and increase variability in the product

As Left Turn also mentioned, volume is subjective. What looks like 100mL to one person, is 105mL to another. More room for potential error.

Weight on the other hand is joyfully consistent with fairly easy calculations. The pull of gravity doesn't change all that much (except at elevation as well).

Given that an accurate digital weight scale can be found for less than $100 and proofing containers could be 5 gallon water jugs... I would say weight is the best way to go.

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Mike, you might already know this, but as well as accurate scales you also need an accurate hydrometer and thermometer to be able to calculate the volume.

The hydrometers and thermometer are not really an extra cost because you should already have them for proofing.

Weighing is by far the easiest way to be very accurate, especially when you are a small producer.

If you would like any help with the calculations then post examples here as there are many here who would gladly show you how.

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I agree that determining the quantity by weight is easier than determining the quantity by volume, but remember, as others have said, that you must determine the proof accurately if you want accurately to determine the quantity by weight, since water and alcohol have different specific gravities. That means that you have to have an accurate way of measuring the proof.

For tax determination purposes, you will not be able to use a densometer, at least not one that you can afford. That means you must use the hydrometer and thermometer. In turn, that means you are going to end up looking at those dreaded tables in the gauging manual anyway and learning how to interpolate. When you qualify as a DSP, TTB sends you a welcoming letter. That letter includes a worksheet designed to take you through the steps in determining the proof using a hydrometer and thermometer. Note that it includes an entry for correction factors.

Correction factors are determined when a lab calibrates your instruments. Hydrometers and thermometers are not accurate out of the box – all of the government hydrometers I ever used had graphs showing the correction factor to apply at different readings. The error does change over the range that the hydrometer reads. Important - people are often more concerned about the accuracy of the hydrometer than they are about the accuracy of the thermometer, but the thermometer must be accurate as well.

As someone said, when you determine tax of bulk spirits, you must do so by weight. That is true. See 27 CFR § 30.36 – “The quantity determination of distilled spirits that are withdrawn from bond in bulk upon tax determination or payment shall be by weight”. But you have to know your definitions. “Bulk spirits” are spirits in containers of greater than one gallon capacity and you can’t remove beverage alcohol in bulk containers to retailers or wholesalers. So, let me ask, when are you ever going to tax determine spirits in bulk? In all likelihood, the answer is never. You will be tax determining spirits in cases. That is not done by weight.

As someone else pointed out, when you determine taxes on bottled goods, you use the stated label proof, bottle size, and number of bottles per case. They cited the correct regulation. Again, this means that you must accurately determine the proof of the spirits in the bottling tank and the fill you are getting in the bottles. And again, you have to have accurate measurement by thermometer and hydrometer, even if you are determining bottle fill by weight rather than by fill flask. TTB allows a .15% by volume drop in proof when you bottle, because there is often a proof loss when you do so, but there is no tolerance on the proof you have in the bottling tank. If the label says 40% (80 proof) then it must be 40% in the tank.

The cut to bottling proof is probably the hardest gauge you will have to make and being able to do so by weight is a lot easier than by volume because you don’t have to allow for the shrinkage in volume as a result of the water molecules fitting between the alcohol molecules. The cut is like pouring a gallon of sand into a gallon of golf balls; you end up with less than two gallons. One hundred gallons of fifty percent alcohol by volume contains 53.73 gallons of water and 50 gallons of alcohol. Weighing is the easiest way to go, but you still must deal with those tables again.

I have never made adjustments for altitude or any difference in air pressure. When you determine alcohol content in wine using an ebulliometer, which we used to do when making wine spirits additions, a change in pressure can throw you off, because you are using the difference between the boiling point of water and the boiling point of the wine to determine how much alcohol is in it. But the specific gravity of 40% alcohol is .93426 in air and .93418 in a vacuum, so the difference is 0.00008, which is negligible. If you wanted to be that precise, then Table 6 of the gauging manual will tell you the figures, but I’m going to guess that the error in your calibrated instruments is greater than any error attributable to differences in air pressure. Such calculations are not included in the steps for determine either the alcohol content or the volume of a liquid.

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Thank you Dunbar that puts things into perspective.

I think I have made a decision on a scale and would like to see what you all think.

It’s a floor scale from USA scale

Four high quality load cells to ensure that the unit is completely accurate

Designed for impacts and rugged use without worrying about damaging the scale

Large deck measures all diamond plated steel non-­‐slip

Large 2” LED display

Equipped with a rechargeable battery as well as a 20 ft Steel braided cable

Tare function covers this versatile unit’s full capacity range.

Counting function enables workers to focus fully on the job at hand

NTEP Approved (Legal for trade)

Plate Thickness: 1/4” Diamond Steel

Weighing Modes: LB / KG

Capacity: 500 x 0.1 lb or 1,000 x 0.2 lb

Accuracy: 0.1 lb or 0.2 lb

Overload Protection: 100% OL

Platform Height: 3.5” H

Warranty: 5Year Manufacture Warranty on base;

1 Year Manufacture Warranty on electronics.

Cheers,

Mike

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I'm glad someone else asked. I've got to keep reminding myself not to venture outside of my area of expertise. That does not include the merits of one brand of scale vs. another.

Good luck.

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........

Weight on the other hand is joyfully consistent with fairly easy calculations. The pull of gravity doesn't change all that much (except at elevation as well).

Just to add some more useless nerdery to the mix and qualify this statement, the elevation change due to being on a mountain doesn't play as much an effect on the pull of gravity as the Earth's non-spherical shape. Since it's more like a ball smushed from the North and South Poles, points at the Equator are a good bit further away from the center of the Earth than points nearer the poles. I think it may even be suggested to have a noticeable enough effect to matter to Olympic high-jump records?

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  • 2 weeks later...

........................................................................

Capacity: 500 x 0.1 lb or 1,000 x 0.2 lb

Accuracy: 0.1 lb or 0.2 lb

........................................................

Cheers,

Mike

I am not sure if you realize these scales won't be accurate enough for weighing lighter items.

I don't work under TTB rules but I am reasonably sure your HYDROMETERS need to be accurate to 0.2 proof. Proof scale goes to 200 so the accuracy is 0.1 in 100

Your scales need to have at least the same accuracy otherwise it is pointless having accurate hydrometers.

The scales mentioned here will not be accurate enough if you are weighing anything less than 100 lb

A common measurement is weighing the contents of 1 bottle. With these scales you could be 45 grams out.

For individual bottles the scale needs to be accurate to 0.5 grams or 0.001 lb

You need at least 2 scales

Pete

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Hi Pete

From my understanding and talking to TTB as long as I measure no less than 10 gallons a scale that is tested by weight and measures biannually it can weight it in tenths of pounds.

If I measure less than 10 gallons the scale must weight it in pounds and ounces.

Does that sound right?

Cheers

Mike

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Mike,

10 gallons US weighs about 83 lb, so the TTB guy says 0.1 lb in 83 is in the same ball park as my deduction of 0.1 in 100 calculated from hydrometer allowances.

Remember TTB is always right (even if they are wrong ;) )

But the statement that at less than 10 gallons your scale needs to read in ounces is only correct down to about 4 gallons.

At less than 4 gallon the scale needs to be accurate to fractions of an ounce.

see my post #18, above

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