Exploring Low Tech Food Dehydration to Increase Profits on Small Farms

Experience with year one of a SARE Farmer Grant, at Jug Bay Market Garden in Maryland

Jug Bay Market Garden

We grow mixed vegetables, cut flowers and herbs on about seven acres in southern Prince George’s County. We market primarily though a CSA delivering to Washington, DC. We have been growing since 2001.

Our Farm is Facing: 1) increasing competition & changing market 2) fresh produce and flowers going to waste due to seasonal time crunch3) Insane increase in deer pressure

The idea for this project emerged from:

1. Seeing the need to reduce waste on our farm and increase profits with value added products.

2. Pricing out commercial dehydrators and experiencing sticker shock at the jump from $30 home units to $20k for quality commercial dryers!

3. Research demonstrated that there are promising existing low cost designs available that have not been tested in our region.

4. Kale Chips are all the rage.

The Two Dryers

We built and tested two very different dryers with several farm products.

1) an extremely low cost low tech passive solar dryer designed by UC Davis Professors James Thomson and Michael Reid.

2) A homemade version of a commercial scale electric cabinet dryer designed by a UC Davis Grad Student.

Construction Costs

• Materials for Cabinet Dryer $500

• Materials for Solar Dryer $100

• Trays $300 or less

• Labor for Building $1000

Cabinet Dryer

$500 in materials

Includes fan, heater and side vent.

Large capacity for 18 2 by 2 trays

Dried tomatoes in 48 hours, kale in 12.

Dried Herbs from the Cabinet Dryer, August 2013

Inside view of Cabinet Dryer with tomatoes and mint

Click icon to add picture

Summary of Cabinet DryerPROS CONS

- Great for tomatoes and eggplant and peppers

- Can run overnight- No loss of color in product

- Less flexibility for larger items- Can overheat- Costs money to run- Higher Construction Costs- Requires weather protection (we

used a hoophouse)

Solar Dryer• Very low cost, can be built for under $100

• Uses the chimney effect to increase air flow over product and speed drying times

• Dryer has been tested in many countries around the world for mangoes, tomatoes etc.

• We found it very effective for greens but did not dry tomatoes and other high moisture crops fast enough.

Solar Dryer

preheat section 2’x2’ trays separated by about 3”

Slide Credit: James Thompson, UC Davis.

Solar Dryer

The chimney without plastic, solar dryer

Solar dryer bermUnder construction

Solar Dryer in use

A Word on Drying Trays (Donut Screens)Why stainless?

$286 for shared set of trays ($15 each for 18 with shopping around)?

Modified designs to use them interchangeably

Could go down to 18 by 18 to fit in a dishwasher

Trays inside cabinet dryer, same trays used in solar dryer

Summary of Solar DryerPROS CONS

- Excelled at greens, herbs and flowers

- Variable space very helpful- Almost Free to build - Free to Run, Passive Solar

- Tomatoes did not dry well- Had moisture problems we are

working to correct- Some products lost color

Results

Flowers

Basil/herbs

Sweet Potatoes

Tomatoes Kale Chips

Peppers

We focused our testing on these six crops

• We collected data on weight of products before and after drying.

• We compared results between the two dryers

• We recorded impressions from a team of tasters including chefs who support our farm.

• This project will continue through 2014 and the grant will be complete early 2015.

Sample of Tasting Results: Kale Chips

appearance taste color texture overall comments

Kale Chip w salt and olive oil 5 3 5 4         

  5 3 5 3 4(oil tastes a little strong, needs salt)

  5 3 5 5 3(vinegar and salt would be good)

  4 3 5 4 4(a little like cellaphane, breaks up)

  4 3 5 4 4       

  5 5 5 3 5exellent      

Chef Tom 4 5 5 5 5stems should be removed, glass packagaing?

  4 2.5 4 4  needs more salt    

AVERAGE 4.5 3.4 4.9 4.0        4.2

We held a taste testing with 7 participants in December. We tested products on a 1-5 scale for appearance, taste, texture and overall impressions.

Data Collection SheetDate Dryer Prep Hours

bachelor button 19-Jun solar removed heads 24 hours

cabbage 20-Jun solar outer leaves 5 hours

herbs/mix 19-Jun solar single layer 5 hours

tomatoes 7-Jul solar sliced, seeds removed 5 hours

calendula 15-Jul flower heads removed 12 hours

spearmint 20-Jul solar on stems 12 hrs

okra

Tomatoes 30-Jul electric sliced, seeds removed 48hrs

Basil 30-Jul electric leaves removed from stem 24 hrs

Eggplant 2-Jul electric sliced 1/2 inch 48hrs

Eggplant 2 30-Jul electric sliced 1/2 inch 24hrs

Tomatoes2 1-Aug electric sliced, seeds removed 48hrs

Tomatoes3 10-Aug electric sliced, seeds removed 48hrs

Tomatoes3 12-Aug electric sliced, seeds removed 24hrs

Basil2 30-Aug electric leaves removed from stem 24hrs

Basil3 10-Sep electric leaves removed from stem 24hrs

boc choy 10-Sep electric in tray 24 hrs

sweet potatoes 0ct 17 electric sliced, food processor 12 hrs

Kale with olive oil 2-Nov electric in tray 12 hrs

Kale with olive oil 2-Nov electric in tray 12 hrs

Product PotentialDried tomatoes and tomato basil mix received great reviews.

Kale Chips: Packaged in plastic or sold “fresh” at market in paper bags have great potential and are very popular.

Sweet potato chips need another round of effort, texture was off but lots of potential, great flavor.

Dried Flowers to add to Farmers Market sales are a good add-on.

Packaging Note

We used a basic kitchen scale and a Foodsaver vacuum sealer to pack the products in plastic bags and mason jars.

We plan to develop a label and test different packaging this season.

We received feedback that people would prefer glass or paper and want to work on that piece in 2014.

Sample package

Upcoming Needs and Plans

• Get the farm certified as a “farm kitchen” to legally sell value added products in Maryland

• Address moisture issues in solar dryer by putting it up on a platform or table.

• Perfect and finalize recipes in consultation with food safety and chefs

• Finish packaging, learn to use glass

A Few Resources:

ATTRAUSDAUNCUC Davis

I have lots of resources to share that I will post links on my website, thelettuceedge.com

tanyatolchin@verizon.net@tanyatolchin

Special Thanks to: o All the rock stars at NE SARE

o The Great Farmer Scott Hertzberg for growing everything we dried

o My Tasting Team esp. Chef Tom Mueller, Pineapple Alley Catering

o Jim Thompson for all the advice from California

o Ross Williams, fish biologist turned dryer builder

o Maryland Organic Farmers, CASA and Acres USA for helping to share the findings