About Bottle Fill Level, Weight versus Volume Measurements, and Head Space

Culinary Solvent is pure ethyl alcohol (ethanol) sold in pints, quarts, gallons (consisting of four quart-sized bottles), five-gallon jugs, and 55-gallon drums.  Depending on your bottle size, there will be a small portion at the top that makes the bottle look like it wasn't filled all of the way. 

Some customers have weighed their bottle of Culinary Solvent in an effort to see how much liquid is contained in the bottle, and the results of weighing in ounces can often add to the confusion.

This blog post is intended to clarify how we fill, how much is contained in each bottle, the purpose of the head space in the bottle, and provide more information on why a 32-fluid-ounce bottle weighs less than 32 fluid ounces (fl. oz.) when placed on a kitchen scale.

Why Isn't the Bottle Filled to the Top?

The bottles we source are designed to be leak proof.  In addition to the special design of the cap and threads, leak proof bottles are also slightly oversized.  Filled to the neck, our quart bottles can technically hold 33.6 fl. oz., and our pint bottles hold 17.5 fl. oz.  The extra room in the bottle, known as head space, is part of the bottle's design for safety and is provided to give the liquid contents room to expand or contract due to changes in temperature without compromising bottle integrity throughout transport or storage. 

About Thermal Expansion

Glass bulb thermometers are a great example of the thermal expansion that is possible with ethanol temperature changes.  The red liquid contained in the bulb and stem of the thermometer is ethanol, which replaced the old-fashioned silver mercury thermometers.  Even small changes in temperature will affect the overall volume of the liquid, which is indicated by the liquid's level moving up or down the stem.  

How to Confirm your Bottle Contains the Amount Stated on the Label

There are two methods you can use to confirm the bottle contents are accurate to the label: measure by volume or measure by weight.

How to Measure by Volume (Quickest)

This method is the simplest, quickest way to measure the contents of your Culinary Solvent bottle.  Obtain a measuring cup and pour the contents into the cup.  Pint bottles will contain 16 fl. oz.; quart bottles will contain 32 fl. oz.  After confirming, carefully transfer the contents back into the bottle using a funnel.

How to Measure by Weight (Most Accurate) 

Measuring the contents by weight is the most accurate method and can be done without removing the liquid from the bottle.  We recommend measuring the bottle using metric units (grams) to alleviate the confusion presented by ounces and fluid ounces.  All digital scales have the ability to measure in metric (grams) and imperial units (ounces).  Please refer to your scale's instructions if you are uncertain on how to change units measured.

How Much Does 32 Fluid Ounces of 200 Proof Ethanol Weigh?

Thirty-two fluid ounces of 200 proof ethanol weighs 26.34 ounces (oz).  Converted to metric units, 26.34 oz is equal to 746 grams (g).  Including the weight of the bottle and cap, your quart of Culinary Solvent should weigh about 810 g total.

How Much Does 16 Fluid Ounces of 200 Proof Ethanol Weigh?

Sixteen fluid ounces of 200 proof ethanol weights 13.17 oz. Converted to metric units, 13.17 oz is equal to 373 g.  Including the weight of the bottle and cap, your pint of Culinary Solvent should weigh about 405 g total.

What If My Bottle Weighs a Little Less or a Little More?

How much each bottle and cap weighs varies, sometimes by as much as 4 g.  Also, the permittable tolerance in our bottle fill procedure can affect the final contents by 1-2 g (or 1%).  Combined, your bottle may weigh a little more or a little less by anywhere from 1-6 g.  This variance is normal. 

But Why Does my 32 Fluid Ounce Bottle Weigh Less than 32 Ounces?

The density of the liquid inside the bottle, coupled with some natural confusion presented when using the word "ounces" to measure both volume and weight, can explain why your 32 fl. oz. bottle weighs less than 32 oz.  Measuring in metric, where grams denote weight and liters denote volume, can help you find the most accurate weight possible.   

Converting Fluid Ounces Directly to Grams: Why It Isn't Possible

Because the fluid ounce is a measurement of volume and the gram is a measurement of weight, it is not possible to convert fluid ounces to grams without first knowing the density of the material being measured.

Using the numbers presented, the contents of one 32 fl. oz. bottle of ethanol (with a density of 0.823 oz/fl. oz.) should weigh approximately 26.34 oz on a scale.  The average weight of an empty bottle and cap comes in at about 2.5 oz, pushing the total weight of an unopened 32 fl. oz. bottle to about 28.8 oz.  

About Density of 200 Proof Ethanol

Density is the measurement of a material's mass compared to the volume it displaces.  The density of water is 1.00 grams per milliliter (g/ml).  This measurement for water is equivalent to 0.9587 ounces per fluid ounce (oz/fl. oz.).  Thirty-two fluid ounces of water, ignoring the container holding the water, will weigh about 30.7 oz on a digital scale.

However, the density of 200 proof ethanol is significantly less than water, measuring in at just 0.789 g/ml.  Converted to imperial units, the density of ethanol will be 0.823 oz/fl. oz.  The difference in density is the reason why a 32 fl. oz. bottle of ethanol weighs less than a 32 fl. oz. bottle of water. 

How Bottles of Culinary Solvent are Filled at the Distillery

We use a four-head bottle filler at the distillery, which, as the name implies, allows us to fill four bottles at one time. Our bottle filler is calibrated each bottling run, which ensures an accurate and consistent fill throughout the run and adheres to all regulations.  In addition to calibration, each bottling run has a fill test performed at the beginning, middle, and end of the run to ensure consistency throughout the entire process.  The allowable tolerance for our bottle filling system is a 1% difference, positively or negatively (or about 1-2 g).  For example, a quart bottle containing 746 grams of ethanol, this permissible tolerance variance is 8 ml or 1.5 teaspoons (tsp) of total liquid.