Applications | How to Perfect the Taste of Your Beverages with Control Flasks

How Control Flasks are Used

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A control flask, specifically control drink flasks, are designed to equate, in terms of capacity, an empty, dry container. The flasks, when properly filled, will hold the exact same content as a bottle and can be used to check proportioning accuracy. The contents can also be used to check brix, color, acidity, and other comparative values.


In the beverage industry, the control flask is typically used to prepare beverages prior to the bottling and canning stages of production. Specifically, the control flasks are used when determining the ratios for beverage syrups. This is especially crucial when producing mixes, whether they are premixes or postmixes. As in, whether the drink mixes or beverage syrups are being made to get canned or bottled directly, or if the syrups are being created to then get packed up and shipped out to replenish drink fountains.

Most beverage companies have their own specific bottling proportions or ratios. Using the control flask, a skilled lab technician will hand mix a control drink with the correct Brix. This control drink is the standard or level of quality that the line drink (the mix that is currently in production) needs to match in order for it to pass quality control.

What is Brix?

Brix is the sugar content found in the solution, and is a unit of measurement/value typically used in making carbonated beverages. This value is referred to when determining whether or not a product has the correct amount of sweetness.


This is to maintain the quality, mouth-feel, and shelf-stability of the premixes and postmixes. A control drink must be prepared every time a new batch of syrup is produced or if the same batch is being used the following day.

What is a Premix and a Postmix?

A Premix is a ready-mixed, ready to drink mix that identical to the drinks in the cans or bottles. This is ready to be canned or bottled.

A Postmix is a bag or container of syrup that gets shipped to places that typically have a soda or drink fountain of some sort, where they will then be hooked up to a machine. These are just concentrates that have not been mixed or carbonated yet.

By creating a control drink to periodically test the quality of the line drink and compare Brix values, any inconsistencies can be corrected. Factors that can affect the mixes are usually other ingredients that can be found in them, or just outside forces like acids (which help balance the flavors of the drinks as well as provide extra shelf stability) and higher temperatures.

When checking quality, the Brix values of the line drink should match the Brix value of the control drink. If the line drink has too high of a Brix value, than the production has too much sweetness. If the line drink has too low of a Brix value, than there is not enough sweetness. That is when the proportion of invert sugar needs to be adjusted.


Invert sugar is a necessary ingredient in order to flavor drinks, as well as provide sweetness. It is created when sucrose is heated to break apart the glucose and fructose molecules. This creates a sort of liquid sugar, which is easier to mix into cold liquids then crystallized sugar. It also helps develop flavors, and – as mentioned before – adds body, enhances the mouthfeel, and makes products more shelf-stable. An example of an invert sugar is high fructose corn syrup.


Terriss Ind. supplies a variety of control drink flask sizes ranging from 1oz all the way to 128oz. See the rest of the website for our full selection. Call 800.342.1611 (within the USA) or 732.988.0909 (international) to place an order today. You can also contact us directly here.

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