Monthly Archives: December 2012

Some Good Data on Sun and Solar Drying

I have always been a promoter of sun and solar drying, because they allow people to convert perishable fruit, often available at low or no cost during the season, into a stable product that can be stored until the next season at almost no or low cost. All of this is to minimise the costs of electricity in domestic houses, which also have a significant impact on reducing the business gas prices of a particular household.

This article provides some good information on the drying process, that helps in deciding how to actually dry.

The article is an in depth one and gives some really interesting data on drying rates. It compares theoretical with measured rates and is then able to model the progress of drying with this data. The graph below is a really clear indication of the main difficulty of solar powered systems – they only work for a part of the day.

This is particularly important in drying, were it means that sun drying carries on for 3 days. This is because, as the graph shows, drying actually only carries on for a fraction of the day. This fraction depends on the location. This is obvious, but for me only really became clear when I saw this graph!

This has implications for how you run your drying. First of all, it’s no good having a nice social day picking, transporting, washing, selecting and preparing your fruit and getting it out into the sun in the late morning or even worse the afternoon. If you do you are going to need four days to dry. More importantly the fruit will be wetter at the end of drying on the first day and therefore more likely to spoil overnight. So rise early and get the fruit ready for the moment when drying can start. Secondly, because the whole drying period until your fruit is shelf stable is many times longer, the cleanliness and hygiene of the plant become more important to avoid spoilage and loss.

The two images in this post are from the online journal at http://www.ajfand.net/Volume12/No7/Mercer11020.pdf

 

Soup Packet – Climate Change and Sustainability Improvements

Something as humble as a soup powder packet can be reengineered to reduce its impact on the environment.

from: FOODStuff SA
(click image for full story online)

click the image to visit the Foodstuff SA website

What is interesting is the effort it takes and the focus on food quality that lies at the base of all decisions.

The statement that the most important thing is that the customer can feel good about asking the right choices for the planet is debatable. It's might be important to consider the impact on product cost and the sustainability of the effort when considering where to focus attention.