Weigh your liquor, wine, or draft beer for better inventory management.
Every man and woman will come to a point in their lives where they have to decide whether or not to re-evaluate their bar inventory.
Okay, maybe not for everyone, but it is something that every bar manager or owner will think about.
You are reading this right now, so it must be today.
I won’t try to convince you about weighing your liquor bottles or kegs. If you want to have an accurate inventory, you must weigh all your products.
I will address some common myths about how to weigh liquor inventory. Why are they wrong? How to properly weigh liquor, wine and draft beer.
If you decide to weigh your inventory, I will also help you choose the right scale.
Okay, ready? Great, let’s get started…
You don’t have to weigh your draft beer and liquor.
1) A digital scale can weigh in ounces for wine and liquor bottles. A scale large enough to hold kegs, which are typically weighed in pounds/ounces.
2) A calculator, pen and paper.
3. The specific gravity (density) of each product you will weigh.
It would help if you had the density to make each product. Yes, yes, you do. This is where the majority of inventory weighing mistakes occur.
My usual thinking process is: I’ll get a scale to weigh each product before a shift and then again after.
A bottle weighing 41.7 ounces at its beginning and 29.8 by the end must weigh 11.9 ounces.
Another way to find out how much liquor remains in a bottle is to weigh it and subtract its tare weight (empty) from it.
Both seem to be logical.
Both are incorrect.
Here’s the problem: fluid ounces do not equal weight ounces.
Kahlua is an example. A 750 ML Kahlua bottle holds 25.4 fluid oz. However, if you were to weigh just liquid, would it weigh 25.4 ounces?
The 25.4 fluid ounces Kahlua weighs significantly more than the 25.4 ounces.
Why? Because of its density. Density is the thickness of a product.
Water has a density of 1. A liquor that is 80 proof is lighter or thinner than water, so it has a lower density in the.9 range.
Cordials and liqueurs will be thicker than water, so their densities are greater than 1.
The product’s density determines how well bartenders can layer shots. Higher-proof liquors will float on top of lighter ones.
Okay, now what does all that density stuff mean?
To get an accurate inventory, you must adjust for the product’s density when weighing liquor, wine or draft beer.
A final point on densities: a density can be dynamically changing.
This means that a product’s densities will vary depending on the temperature. The density of a product can be affected by changes in temperature.
There will always be an error margin when weighing inventory. The margin of error, which considers density changes, is typically 2% or less.
This is why weighing your bar’s inventory is the most accurate inventory method.
Comparatively, eye-balling, now called weightless inventory by some eye-balling inventor apps, has an average margin for error of around 15%.
It is a huge difference in inaccuracy!
Okay, enough of the density information overload. Let’s go back to how to weigh your inventory.
It would help if you now had all you needed: a calculator, pen, paper and a scale.
First, make sure you do some calculations for each product. This will ensure that you are correctly converting fluid ounces from weight ounces.
1) Take a full container of each product and weigh it using your scale. To determine the product’s usage, you will need to know the full weight of each product (and, if possible, the keg weights).
2) Next, calculate the product’s adjusted fluid-ounce size using its density. Bottle size (fluid Ounces) = adjusted bottle size.
3. Next, calculate the bottle weight tare weight using that adjusted bottle size. Bottle tare = full bottle weight minus adjusted bottle size