Exploring low-tech food dehydration to increase profits on small farms
Our grant explores low-tech solutions for dehydrating crops on our farm to help reduce waste and increase farm profit from new value added products. In the late winter we built two dehydrator models to test on our farm. The first model is a passive solar stack dryer that utilizes the chimney effect to dry products with increased air flow. Since we have such high humidity in our area, we will also built an electric cabinet style food dryer.
Beginning in late July, we began testing both dryers using greens, tomatoes, flowers, sweet potatoes, eggplant, hot peppers, basil and other herbs. Overall, we found both dryers to be a great asset to our farm and each has particular strengths and weaknesses depending on the crop we are drying, weather and other factors. The electric dryer is already working very well. We plan to make only minor modifications in 2014 to it. We plan to make major modifications to the solar dryer in 2014 to get better performance. We plan to build a table to move the dryer off the ground to reduce moisture.
We packed our products using a vacuum sealer in plastic and glass, and held tastings in December to get feedback on six of our dried products: 2 kale chip recipes, dried tomatoes, basil, spearmint and sweet potato chips. We received useful feedback and are now poised to make adjustments and continue testing in year 2014.
Since we are not yet certified to sell the dried food products, we did some experimental marketing of decorative dried products this season. We brought our dried flowers to a large regional Green Craft Fair and sold them at farmers market and other events. We also created some herbal bath salts using the dried herbs.
Upcoming goals include getting our kitchen certified as a “farm kitchen” and beginning to clear some of our recipes with the Maryland Department of Health so we can start marketing food products in 2014. We will also send some of our dried packed products out for laboratory testing for dryness and shelf stability this winter.
Building Phase (Winter/Spring 2013)
We relied heavily on two existing plans to build the dryer. We made a few modifications based on our judgment and consultation with the Maryland Food Safety team. One dryer is passive solar and one includes an electric heating element. The passive solar model follows UC Davis plans for a passive solar stack or chimney dryer. The second dryer utilizes electric heat and a fan,, and it also based on plans from UC Davis. It was more expensive to build and run but played an essential role in drying this season.
We decided to use stainless steel trays instead of plastic and to modify the specs so we could use the same trays interchangeably between the two dryers. This worked out well because most of the time we used one dryer or the other.
Testing the Dryers (Summer/Fall 2013)
Solar Dryer Performance Notes
The solar dryer was amazing during our first tests in June and July. We were able to dry greens and herbs within hours and pull them out before nightfall. The color remained vibrant and the materials appeared fully dried and crumbly to the touch.
Later in the season we ran into several challenges with this dryer, especially when trying to dry tomatoes. The tomatoes required more than one full day in the dryer and if left overnight would attract insects to the fruit. When the dryer is hot, insects seem to stay out but as it cools at night they will be drawn to the residual warmth. Unloading and reloading is labor intensive so it seems ideal to dry products in the solar dryer that take one day or less like the herbs and flowers.
A second problem with this dryer is that the area did not drain well after big rains. Since we dug around the area to create a raised bed area for drying, the rain tended to pool near the dryer and take a few days to dry after a hard rain. This winter, we plan to modify this dryer by building a platform to dry the product on. This should reduce moisture since it will be off the ground and reduce pest pressure as well.
The solar dryer excelled at drying herbs and flowers with an initial low moisture content. The basil, rosemary and spearmint all dried within hours and had similar color to the herbs dried in the electric dryer. Another advantage to the solar dryer is the elbow room and variable headspace. The plastic cover could be raised and lowered and larger items could span more than one tray. In this way we were not limited by tray size and could pile on some awkward large items like three foot stems of larkspur, branching basil, hard neck garlic with stalks etc.
Electric Dryer Performance Notes:
The electric dryer did very well for us, with just a few little hitches along the way. Everything we put in the dryer dried very nicely within 24-48 hours and we could leave it running consecutively. The dryer is very clean and pest free. On the downside, we were limited to the tray size which meant a little more prep for loading the dryer efficiently was needed. It did require checking especially when the greenhouse it was sited in was already hot to make sure it wasn’t getting too hot. This winter we want to modify the electric dryer by replacing the fan and possibly installing a device to help the vent open automatically as needed.
This fall we brought our dried flowers to a large regional green craft fair and sold arrangements. This winter we held a successful tasting event where participants tried six of our products. We included our chef consultant Tom Meuller in the tasting. We were quite pleased with the results of our tasting (attached) and we feel we can be responsive to the feedback. The tomatoes, kale and basil all received great reviews and we hope to have these products market ready in 2014. Some of the dried flowers like the cornflower below also have potential for sale as decorative food items like such as confetti for catering trays.
This winter, we will refine our packaging and design a label. We would like to try shifting to mason jars and also selling “fresh” dried kale chips in paper bags for immediate consumption at farmers market.
- dried flowers, solar
- dried flowers ready for sale
- sweet potato chips ready for tasting
- Results of Tasting
Impacts and Contributions/Outcomes
This winter I will be part of a panel at the Future Harvest CASA conference with Jason Challandes and other regional farmer grant recipients. I also have an arrangement to publish an article about this project in Acres USA Magazine which has an excellent nationwide reach to farmers and the farm community. I also plan to present at the Maryland Organic Farmers winter meeting.
Our project was featured in our county Food and Farming newsletter in July. http://myemail.constantcontact.com/Prince-George-s-County-Food—Farms-July-E-Newsletter.html?soid=1103622714568&aid=f4XLI5mtois.
We have shown our dryer to neighbors and friends in the farming community and allowed other farmers and gardeners to dry some of their excess harvest in our dryer. We hope to continue to share this resource as a community dryer so others can benefit and learn the process.
Finally, we want to say thank you to SARE. Everyone has been so easy to work with and helpful. We are looking forward to a successful second year and robust final report. Of course, if we left anything out of this report we welcome your questions!
Thanks again and Happy New Year!