Food powder mixing

Mixing of food powders is a very widespread operation in industries, but how to successfully mix powders and get an homogeneous mixture ? And which mixer works best with food powders ? This page is giving some elements of answer.

1. Introduction : dry-mixing of food powders

A large amount of foodstuffs is sold as a powder, which are very easy for the consumer to keep and use. For many of those powders it is actually a formulation rather than a single ingredient which means that a mixing step must be done to have an homogeneous mix of the different ingredients. This is also only thinking about the end product, but in factories a mixing of powders is also done very often prior to other process operations, for example the mixing with a liquid.

Large industries perform those mix for all kind of products, for example milk powders, infant formula, chocolate powder, coffee...etc...

But small businesses find in powder mixing an apparently easy way to add value to their product and find consumers. It is for example the case for all nutritional complements, often associated with sports, that are sold as a mixture of base with some small ingredients (minerals, vitamins...).

Now, how to best mix food powders ? Which mixer to chose ? The page below is actually proposing to split cases in between business size, and as a function of the materials to mix.

2. Food powder mixing in Small scale businesses

Small food producers which are starting a food mixing business or units must be very flexible and have small batches to answer to small orders, more and more taken directly online, and being able to propose a large range of products.

The operation is therefore quite manual, very often the owner himself is producing the mix when the company is at the start-up stage.

Rotary blenders, such as drum blenders or V mixers are therefore particularly adapted. They do not provide a large capacity, but it is not what is looked for by these companies, but rather ease of use and ease of cleaning.

Figure 1 : principle of operation of a V blender

V mixers, drum blenders and other rotary mixers although they offer an appreciable ease of use should however be selected by those businesses also based on the following elements :

• The degree homogeneity achieved can be lower than other types of mixers having an agitator
• Those mixers are not very effective when there is a large particle size difference in between components
• The mixing time is typically long (10-15 minutes is not uncommon)
• The filling rate of the mixer is low (around 50%, slightly more may be possible in some cases)
• The way to fill the mixer is important, especially for the V mixer

Small businesses should get in touch with mixing specialists to understand their application, correctly select their mixer and operate it.

3. Food powder mixing in Large scale production

For large scale production, the capacity is key in order to be able to compete in terms of costs. As a consequence, the mixing time of rotary blenders such as V mixers or drum blenders is often prohibitive and those mixers have to be replaced by other types, able to mix quicker or even mix continuously.

Figure 2 : design of a ribbon blender

Convective mixers are then used and very often ribbon blenders, double shaft paddle mixers (batch or continuous) or even high shear mixers (although their use is not always required) are found. They also offer usually more robust performances in terms of mixing homogeneity which is an important parameters for large companies often highly focused on quality management to protect their reputation. Such blenders are also often better suited to handle materials with strong particle sizes difference (however they may break those larger powders) and can be better integrated in automated processes than rotary blenders such as V mixers.

On the other hand, operators of these mixers must make sure they have an hygienic design and that they are still cleanable enough to reach the required quality targets. It can be then interesting to consider design allowing large access doors or even extraction of the mixing tools.

4. Suppliers of mixers for food powders

The following companies can supply dry mixers powder mixing production :

• Lessine
• Tetra Pak Powder Handling

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