Walnut hulling and curing

Black walnut processing can be broken down into key steps. 

Black walnuts are grown, gathered, hulled, cured, shelled, sorted and then consumed with various recipe-dependent steps happening prior to consumption.

Each step can be individually optimized or industrialized. Black walnuts cultivars with specific desirable traits can be intentionally planted rather than relying on wild stock. Black walnuts trees can be mechanically shaken to cause black walnuts to fall where and when wanted for easier collection. Industrial scale hulling/husking is a known technology and expired patents are now public information. Curing can be accelerated with added heat or forced air circulation. We know that shelling, sorting and post-sorting can all be industrialized because Hammons Product Company in Missouri does this ever year.

The trouble with industrial scale solutions is that they tend to cost industrial scale money. If decentralized black walnut processing is to emerge, then, as has happened in almost every industry which first centralized and has since seen significant decentralization, the technology must evolve. We don’t know exactly what technology will enable cost-competitive decentralized black walnut processing.  We assume the answer isn’t readily available or else decentralized black walnut processing would already be widespread.

Therefore, we have opted for an initial approach just as step above low-tech. We don’t employ sophisticated controls or monitoring and progressing walnuts through our process doesn’t happen automatically. We employ people. Our hullers are hand-cranked, although we are considering adding a motor to one soon. A manual post-hulling wash step takes advantage of our gravity-driven drainage trench and a well with an electric pump but nothing else. Walnuts are then loaded into a cement mixer along with more water and gravel and the rotation of the barrel drives the abrasion that delivers a final cleaning step. Pre-curing testing for bad black walnuts is as low tech as putting them in a sink full of water and throwing the ones that float into the woods. Our curing approach is passive but aided by solar heating. This is a very straightforward, hands-on approach. We have a process where some work is provided by electricity, some by gravity, some by the sun but most by people.

If we were processing on an industrial scale, this would be an unaffordable approach. However, because we don’t yet know what is needed to deliver cost-competitive distributed black walnut processing, we aren’t investing much in any particular technology. We’re investing in learning by doing. This will demonstrate exactly how much improvement is needed at every processing step and help us focus on only improving the steps that are the most important barriers to a cost-effective process. Our current approach to hulling and curing is visible right here. We will take the same minimalist approach to shelling, sorting and post-processing when we set up this capability in our now-contracted to-be-constructed building. Our goal is to have the building shell completed before the end of this year. Our building site is up the hill at the end of this driveway. Follow the driveway and check out our building site, including a rendering of how the building will look once built.

Our near-term objective is to deliver healthy food using a safe process that doesn’t cost too much to implement.

We’ll figure out how to do it faster and cheaper after we’ve mastered the basics.