Underground cold storage · Valmeyer, IL bluffs · St. Louis metro
Notes from inside a freezer
built in a limestone mine.
I run an underground freezer in an old limestone mine on the Illinois side of the St. Louis metro. This blog is where I write down what I learn: freezer operations, temperature records, maintenance, and what underground storage is actually like day to day.
*From my own operation. Your site will differ.
Who this is for
Cold storage operators
People running freezers, coolers, or dry warehouses who want practical notes on logs, maintenance, and keeping temperatures under control.
Businesses shopping for storage
Food producers, distributors, and brands comparing cold or underground storage and trying to figure out what to ask.
The underground-curious
Anyone wondering how a 120-year-old limestone mine ends up holding freezers, and why the rock helps.
Latest posts
The Checklist That Keeps Our Underground Freezer Running: Daily, Weekly and MonthlyThe daily, weekly and monthly checks we run on an ammonia freezer plant underground, and the real problem from our own logs that each one is there to catch.
When the Hydrometer Lies: Checking Brine Strength in a Freezer's Secondary LoopOur brine read one strength in the field, another in the lab, and neither matched the target. Here's what threw the readings off and how I check brine now.
Snowstorm Behind the Racks: Tracking Down an Air Leak in a Freezer CeilingI walked into a freezer room and found what looked like a snowstorm behind the racking. Here's what caused it, how we sealed it, and what I check now.
1:20 Isn't 120: The Defrost Timer Bug Hiding in Our Controls MigrationOur old controllers read a defrost time of 1:20 as 80 minutes. The new system read 120 as 120. Why our defrosts kept overlapping, and how I found it.
The Day From Hell: A Smoking Pump, a Sewer Backup, and Half the Freezer Switched OffOne July 2025 week in an underground freezer: head-pressure alarms, half the units off, a smoking pump motor, and a sewer backup. What I took from it.
Free Cold Storage Temperature Log Template (Printable + CSV)Free printable temperature log for freezers, coolers, and cold rooms, plus CSV and calibration logs and the federal rules for storage-only warehouses.
What's coming
- Underground vs. above-ground cold storage: where the costs differ
- What to do when a freezer goes down at 2 a.m.
- FSMA rules for storage-only warehouses, in plain English
- Freezer evaporator icing: causes and fixes
- Humidity and condensation in underground storage
- Questions to ask before you rent cold storage space
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