Product Opportunities with RoastR!

7 Feb 2020

Six months has passed since we introduced RoastR at Snackex in Barcelona. Our RoastR team have been busy testing different snack pellets to learn more about the technology. What type of pellet and shape works best, and what settings are used to produce a great product? Read all about it in this report.

Comparing Vegetable Oil and Salt as Heating Media

The excellent heat transfer in salt was one of the reasons why we developed RoastR. When roasting snack pellets in salt, the transfer of heat is made at the salt granules’ surface. However, when frying a snack pellet in oil, the coverage of heating media is complete on the product, which is very efficient. So, to ensure the same heat transfer in RoastR, we only have to increase the processing time a few seconds. 

Another difference using salt as heating media, is the pick-up of heating media in the product. A fried snack pellet picks-up between 15-35 % of oil, whereas the snack pellet processed in RoastR picks-up a minimal amount of salt (0,1-0,4%).  

How Reliable is the Heat Transfer in Salt?

Performed tests have been made using 14 kg of vacuum salt with following granulometry:

  • > 0,71 mm (< 10 %)
  • 0,10 – 0,71 (> 85 %)
  • < 0,10 mm (<5 %)

This is a slightly larger granule size, compared to salt used for seasoning. To keep a clean processing area, it is important to use as dust free salt as possible and we have reached good results with above vacuum salt.

Ingredient Base and Pellet Shape Affects the Expansion

We have now performed Lab RoastR tests with a large variety of pellets, produced on different ingredient bases, and we have noticed a clear correlation between expansion, ingredient base and pellet shape.

Potato-based pellets, with a simple and open core or with a small size (15-30mm), has a great expansion at 185℃ for 25 +/- 5 seconds.

We have reached a good result with Corn-based pellets, in terms of texture and expansion. However, for more complex 3D shapes a higher processing time is necessary to reach desirable expansion. You could say in general that temperature and time is decided by the pellet shape and base. For instance, simple 3D shapes with a corn-base requires a temperature of 195℃ for 30 seconds, whilst a complex 3D shape with the same base requires 205℃ and 25+ seconds.

For other ingredient bases than potato, corn and fresh vegetables, the required setting varies a lot. However, we have found it possible to expand pellets with following ingredient bases, but the texture sometimes proves to be a challenge:

  • Shrimp (Score 5/5 in expansion).
  • Pork Skin (Score 5/5 in expansion).
  • Chicken skins (Score 3/5 in expansion).
  • Seaweed (Score 3/5 in expansion).

Pellets with a High Vegetable Content

The initial tests with Lab RoastR was done with snack pellets with a high content of fresh vegetables. Up until today we have used snack pellets with a fresh vegetable content ranging between 40-45 %. The processing in RoastR results in an ideal expansion of this pellet. 

The taste of the processed fresh vegetable pellet is truly authentic and by just adding a few percent of sunflower or rapeseed oil and salt, the flavor gets even better mediated.

Reasons for Not Achieving Desired Expansion

Did we manage to expand all pellets we processed in Lab RoastR? No, we did not, even if the pellet specification sometimes theoretically pointed towards a good expansion.

We experienced non-successful tests with pellets of all ingredient bases, except for the fresh vegetable pellets,

but we are very confident that an adjustment in the composition will result in desired expansion for those pellets. The most difficult pellets to reach a good expansion result are the ones with complex 3D shapes, since they will not allow salt to enter holes and cavities internally, until the external surface expansion has started. 3D shapes also bring along a risk of a too much salt on the product. 

Temperature and Time

In general, the required processing time can be lowered when using higher temperatures (from 195℃). As with other processing technologies, it is a balance to find the best processing temperature and time. Too long time is bad for your capacity and too high temperature may risk product appearance and food safety. During the

tests, we have operated the

Lab RoastR at temperatures ranging from 175℃ to 205℃, with a processing time between 17-35 seconds. 


The fresh vegetable pellets reach the best result in Lab RoastR. However, there are many products that also reaches a good result. The best expansion will be reached when using open and simple pellet shapes (2D), with a small size (15-30mm). Temperature and time are decided by the pellet shape and base.

If you are interested in testing new pellets with our technology, you are welcome to contact us for a Lab RoastR Trial.