Mash Tuns — Asbestos Exposure Crosswalk
What This Equipment Is
The mash tun is the first major vessel in the brewhouse. Milled grain (the “grist”) is combined with hot water at carefully controlled temperatures to extract fermentable sugars from the malt — a process called mashing. In a large commercial brewery, the mash tun handles thousands of pounds of grain per brew and runs at 150–168°F for an hour or more before transferring to the lauter tun.
Mash tuns are heated either by direct steam injection or — more commonly in large-scale operations — by a steam jacket wrapped around the vessel exterior. That jacket is fed by a steam supply line from the powerhouse and drains condensate through steam traps. The steam-side piping, the jacket itself, and the supporting equipment historically required asbestos-bearing insulation, gaskets, and packing.
Asbestos Products Historically Used Around Mash Tuns
| Product Category | Where on the Vessel | Notes |
|---|---|---|
| Block insulation | Steam-jacket exterior | Calcium silicate or magnesia |
| Pipe covering | Steam supply line, condensate return | Magnesia, calcium silicate |
| Insulating cement | Joints, fittings, jacket-to-vessel transitions | Mixed dry, hand-applied |
| Gaskets | Manway covers, racking and transfer flanges, steam-jacket access ports | Asbestos sheet gasket material |
| Valve packing | Steam supply valves, control valves on the jacket | Braided asbestos rope packing |
| Steam traps | Drain legs from the jacket | See Steam Traps |
Manufacturers Named in Litigation Involving These Products
- Johns-Manville — pipe covering, block insulation
- Owens-Corning / Fibreboard — pipe covering, block insulation
- Armstrong World Industries — calcium silicate insulation
- Garlock Sealing Technologies — sheet gaskets
- A.W. Chesterton — braided asbestos rope packing
- Crane Co. — valves and ancillary equipment
Documented Product References
Images sourced from publicly available product-identification reference materials. Inclusion does not constitute a finding of liability against any company.
Trust Funds That May Apply
- Manville Personal Injury Settlement Trust
- Owens-Corning / Fibreboard Asbestos PI Trust
- Armstrong World Industries Asbestos PI Settlement Trust
- Garlock Sealing Technologies LLC Asbestos PI Trust
Trades Most Exposed at Mash Tun Work
Pipefitters, insulators (Heat & Frost), brewers’ mechanics, millwrights during rebuilds, plant operators handling routine valve maintenance.
Jobsites in the Network Documenting Mash Tuns
- Anheuser-Busch Brewery, St. Louis, Missouri
- See companion pages: Brew Kettles, Lauter Tuns, Fermentation Tanks
Compiled from publicly filed asbestos litigation, EPA / state-DNR records, and industry-publication histories. Product and company references reflect what has been alleged or documented in publicly filed litigation. This page does not constitute a finding of liability against any company. Not legal advice; consult a licensed attorney about your specific situation.