Characterizing Chestnut 'Cure' as a Function of Time, Temp & RH, Based on Nut Size, Color and Shape

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2023: $15,000.00
Projected End Date: 03/31/2025
Grant Recipient: Mountain Grown Chest
Region: Southern
State: North Carolina
Principal Investigator:
Dr. Ron Fritz
Mountain Grown Chest


  • Nuts: chestnuts
  • Additional Plants: trees


  • Crop Production: crop improvement and selection, forest farming

    Proposal summary:

    The solution:

    To inexpensively solve the difficulty of determining when chestnuts are ready for consumption (by visual or tactile inspection, particularly for those kept at low temperatures and high humidity to maximize shelf life), this solution is to develop guidelines via statistically designed experimentation, the results of which can reasonably forecast curing rates under various temperature/RH circumstances.  So given knowledge of the thermal and RH history of the nuts, one can then prescribe the time required at a certain temperature/RH combination to accelerate, delay or maintain cure to bring nuts to optimal sweetness at the intended time of consumption/use.

    With this grant I will be funding a partnership with a major university (Clemson) and/or analytical lab (Pace - Asheville) to carry out this designed experiment (described in the 'Approaches and Methods' section of this submission).  This study and its results will then be peer review published (open access) in a suitable journal for use by academia, industry and consumers with the aim of educating and arming them so that more of what the chestnut has to offer can be obtained.


    Project objectives from proposal:

    Chestnuts will be supplied by Mountain Grown Chestnuts, LLC, Burnsville NC 28714, from the 2023 harvest.  They will be kept at 32 F and 90% humidity until pulled from the cooler for 72 F/60% RH curing.

    The study will be comprised of a 2^5 full factorial, fully replicated (n=2) designed experiment.  Factors and levels will be as shown below.  The primary response will be '% soluble solids' (brix content) and will be determined via best practice 'wet chemistry' (WC) methodologies, done for each of the 32 treatment combinations (with '0.15' lbs. of nuts/treatment combination):

    Harvest Date Day 1 Day 15
    Nut Size Small (< 0.75" diam.) Large (> 0.75 diam.)
    Nut Color Light Dark
    Nut Shape 1 Flat Side (End Nut) 2 Flat Sides (Middle Nut)
    Burr When Dropped Open Closed

    The above full factorial experiment will be conducted at four different dwell times as shown below (with all dwells at 72 F and 60% RH):

    • 0 hrs. dwell at 72F/60% RH
    • 48 hrs. dwell at 72F/60% RH
    • 96 hrs. dwell at 72F/60% RH
    • 144 hrs. dwell at 72F/60% RH

    Statistical linear models for each of these 4 dwells will be created, from which curing curves will be developed for combinations of the statistically significant factors found.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.