Sauce production: how product composition determines process design

Process line design: continuous processing versus batch production

Red sauce production lines usually consist of several process steps, including ingredient dosing, heating, homogenisation where required, pasteurisation and buffering. For smooth sauces such as ketchup, a homogeniser or colloid mill can be used. For sauces with coarse particles, homogenisation can be omitted to avoid damaging the particles. Another option is to mix and smooth the sauce base first, so the binding ingredients are properly absorbed, and add the larger particles afterwards.

Continuous processing with a Kelstream® scraped surface heat exchanger is particularly interesting at higher production capacities. It allows precise control of residence time and temperature, which helps maintain consistent product quality and limits mechanical stress on the product. One example is the red sauce line with a capacity of over 4,000 kg per hour that we built for a producer in the Caribbean. There, three Kelstream heat exchangers handle heating to pasteurisation temperature and two-stage cooling. Depending on the product and process conditions, this approach can also improve energy efficiency per unit produced. For sauces with solid particles, heat penetration to the core of the particles must also be taken into account to determine the required time and temperature.

Continuous production is also used for mayonnaise and other emulsified sauces, but batch production remains a suitable option as well. It offers more flexibility when recipes, production volumes or customer requirements vary. In a continuous bulk process, specific ingredients can also be added just before pasteurisation and filling. This keeps the product base consistent during product changeovers and reduces product loss and cleaning time, as only the last part of the process line needs to be changed over.

White sauces are often produced in batches, as the process sequence fits well with the use of a jacketed cooking kettle: melting the fat, adding the starch, gradually mixing in the liquid and precisely controlling the heating. Modified starches can simplify processing, but temperature and heating time remain important for achieving the desired texture. Asian sauces, which often contain a larger number of ingredients, are also regularly produced in batches.

For white sauces, direct steam injection can result in a whiter end product thanks to rapid heating. However, the different heating profile can affect starch performance, so a different or specifically suitable starch may be needed. The steam condenses in the product and adds water, which must be accounted for when determining the recipe and final consistency.

The choice between continuous processing and batch production is therefore not universal. Continuous systems usually require a stable supply of ingredients and a fixed recipe. Batch production offers more flexibility with varying recipes, smaller production volumes and changing customer requirements.