Nancy Shang | Founder & CEO, MICET | Published July 2026
A hot liquor tank (HLT) heats and holds brewing water for mashing, sparging, and cleaning. For most commercial systems, size it at roughly twice your brewhouse batch volume, insulate it if you heat overnight, and match the heat source — electric, steam, or gas — to your scale and floor plan.
The trouble is that most HLT advice online was written for a 40-liter pot with a single element bolted through the side. A 5-gallon strategy and a 30 BBL steam vessel do not scale by the same rules, and getting the tank wrong shows up as a stalled brew day rather than a line on a spec sheet. This guide walks the sizing and heating decisions the way we spec them on 2-, 3-, and 4-vessel systems.
What the hot liquor tank does on a commercial brew day
The HLT is your source of controlled hot water. It heats strike water to temperature for mash-in, holds sparge water for lautering, and supplies the hot water your CIP cycles need at the end of the day. In a 3- or 4-vessel brewhouse it works alongside the mash/lauter tun and the kettle/whirlpool, handling the water side so those vessels stay dedicated to grain and boil.
Two design choices flow from that role. First, whether you heat water inside the HLT or transfer it hot from the kettle the night before — this decides whether you need insulation and how much heating power the HLT itself carries. Second, whether the tank also carries a HERMS coil for mash-temperature control, which we cover further down.
Sizing your HLT: the 2× rule, and when to break it
Size the HLT off your brewhouse working (batch) volume, not the tank’s total volume. Total volume includes headspace you will never fill with water, so sizing off it quietly oversizes the tank and your heating bill. Here is the sequence we use.
- Take your brewhouse batch size. A “10 BBL brewhouse” means 10 BBL of finished wort per batch. That is your baseline number.
- Multiply by 2 for a single-batch day. You need strike water plus sparge water plus a working margin for CIP, and 2× covers that comfortably for one brew.
- Scale up for back-to-back brews. If you plan to run two batches in a day, go beyond 2× — up to roughly 3× the brewhouse volume. The heat exchanger recaptures some hot water off the first brew, but not enough to cover a second mash and sparge, so the tank has to carry the difference.
- Decide heat-in-tank vs transfer-from-kettle. If you will heat water overnight inside the HLT, spec insulation and enough element or steam capacity to reach strike temperature by morning. If you transfer already-hot water from the kettle, a single-wall tank with one small element to nudge the temperature up a degree or two is enough.
- Reserve for cleaning. Every brew day ends in a CIP cycle that wants hot water. Fold that demand into the margin rather than discovering it short at 6 p.m.
- Confirm floor space before you commit. A double-sized HLT is a real footprint on the brew deck. Check headroom and floor area against the brewhouse layout first; some breweries pick a single-sized HLT plus an on-demand heater specifically to reclaim floor space.
The single-vs-double sizing decision has a genuine trade-off, not a cosmetic one:
- Single-sized HLT (≈1×–2×): smaller footprint, lower tank and heating cost, simpler to reach temperature. The cost is that a second brew in one day depends on an on-demand hot-water source; without it, you wait.
- Double-sized HLT (up to 3×): covers double brew days on its own and gives water-treatment headroom. The cost is floor space, a bigger heating load, and — if you heat overnight — a stronger case for insulation to hold temperature until morning.
Compared with the homebrew-oriented HLT guidance that dominates search results, commercial sizing is driven less by a single “correct” multiplier and more by your brew-day cadence: one batch or two, heat-in-tank or transfer.
HLT sizing reference: 300L to 30 BBL
The table pairs brewhouse batch size with a starting HLT working volume. Treat the single-batch column as the default and the double-batch column as the target if you are forecasting two brews per day.
| Brewhouse batch (working vol.) | Single-batch HLT (≈2×) | Double-batch HLT (up to 3×) | Heat source usually paired |
| 300 L | ~600 L | ~900 L | Electric |
| 500 L | ~1,000 L | ~1,500 L | Electric |
| 2 BBL (~230 L) | ~4 BBL | ~6 BBL | Electric / direct fire |
| 7 BBL | ~14 BBL | ~20 BBL | Electric / steam |
| 10 BBL | ~20 BBL | ~30 BBL | Steam / electric |
| 15 BBL | ~30 BBL | ~45 BBL | Steam |
| 20 BBL | ~40 BBL | ~60 BBL | Steam |
| 30 BBL | ~60 BBL | ~90 BBL | Steam |
These are starting points for a quote, not fixed catalog SKUs. Water source flow rate, target brewing schedule, and whether you heat in the tank or transfer hot all shift the final number, which is why we draw the tank against your actual floor plan before building.
Electric, steam, or gas — which heat source?
The heat source is where scale and site constraints collide. A tank that heats fine on three immersion elements at 500L becomes painfully slow to reach strike temperature at 30 BBL. Our brewhouses run all three heat sources depending on the build, and the split below reflects where each earns its place.
| Heat source | Best fit | Strengths | Watch-outs |
| Electric immersion | 300L to ~10 BBL, indoor sites, no gas line | Precise temperature hold; no venting or boiler; lower install cost | Slower ramp at large volume; big HLTs want 3-phase power (single-phase only maintains or nudges temperature); elements need periodic descaling |
| Steam | ~10 BBL and up, multi-vessel plants | Even, gentle heat with no scorch; fast on large volumes; scales across every vessel from one boiler | Requires a steam boiler and its plant; higher capital and ongoing maintenance |
| Direct fire / gas | Budget builds and direct-fire brewhouses | High heat input for low equipment cost | Scorch risk on the vessel floor; needs proper venting; harder to hold a precise setpoint |
A common and cost-effective pairing on smaller systems is a direct-fire or steam kettle with an electric-heated HLT, since the HLT often only needs to maintain water at temperature rather than boil it.
Adding a HERMS coil, and when to skip it
HERMS — Heat Exchange Recirculating Mash System — is a stainless coil submerged in the HLT water. Sweet wort from the mash tun is pumped through the coil, picks up heat from the surrounding hot liquor, and returns to the mash to hold or raise mash temperature without a direct heat source under the grain bed. It makes mash-temperature steps repeatable, which is the whole point of a system you can set and walk away from.
Two caveats worth knowing before you spec one. The coil only transfers heat while the HLT water sits above your target mash temperature, so brewers often hold the HLT hotter than strike temperature during recirculation. And HERMS adds a pump, a coil, and plumbing to clean; if you brew single-infusion styles without step mashes, a straightforward HLT without the coil may serve you better and cost less. We can build the HLT either way as part of a 2-, 3-, or 4-vessel configuration.
Three mistakes that show up after the HLT is installed
- Sizing off total volume instead of working volume. This inflates the tank and the heating load for capacity you never use. Always size against the brewhouse batch figure.
- An uninsulated tank you plan to heat overnight. If you bring water from tap temperature to strike temperature the night before, an uninsulated HLT bleeds heat by morning and the elements fight to recover. Insulate any HLT you heat and hold overnight; a transfer-only tank can stay single-wall.
- Forgetting the second brew and the CIP demand. Undersizing means the heat-exchanger recapture from brew one falls short for brew two, and the CIP cycle competes for whatever hot water is left. Both are predictable — plan the margin in from the start.
A quieter fourth trap: putting a large-volume HLT on single-phase power. One element can maintain or lift temperature a few degrees, but heating a full double-sized tank from cold on single phase is slow enough to stretch your brew day. Spec three-phase where the volume calls for it.
What ships with a MICET HLT
Our hot liquor tanks are built as part of the 2-, 3-, and 4-vessel brewhouse line, with visible configurations from 300L through 30 BBL. Construction is SUS304 stainless (304/316 available where specified), with a CIP cleaning nozzle for clean-in-place, insulation and jacketing where the heating strategy calls for it, and electric, steam, or direct-fire heating matched to the build. HERMS coils, port layouts, and vessel count are configured to the project rather than sold as a fixed package.
On compliance, MICET brewing and brewery equipment carry PED verification under certificate 3N231110.SICS093, issued by Ente Certificazione Macchine Srl against EN 1626:2008 for the Pressure Equipment Directive (2014/68/EU), valid through November 2028. That covers the pressure-rated vessels in a brewhouse build. This equipment has been installed across 100+ countries.
On price: because the HLT is specified as part of a brewhouse rather than a standalone catalog item, its cost is quote-based — the tank size, heating method, insulation, and HERMS option all move the figure. For reference, full commercial brewery systems (from the 10 BBL minimum) run 50,000–80,000 USD; a standalone HLT is priced on request against your configuration.
FAQ
Q: What size hot liquor tank do I need for a 10 BBL brewhouse?
A: Around 20 BBL for single-batch days (the 2× rule). If you forecast two brews in a day, size up toward 30 BBL, since heat-exchanger recapture from the first brew won’t cover the second.
Q: Do I still need an HLT if I have an on-demand hot water heater?
A: For a single batch, an adequate on-demand system can let you run a smaller single-sized HLT. For double brew days, precise mash-water treatment, or HERMS temperature control, a properly sized HLT still earns its place.
Q: Electric or steam heating for my HLT?
A: Electric suits systems up to roughly 10 BBL and sites without a gas line or boiler. Steam becomes the practical choice at 10 BBL and above, especially in multi-vessel plants running off one boiler.
Q: Can you add a HERMS coil to the hot liquor tank?
A: Yes. The HLT can be built with or without a HERMS coil as part of a 2-, 3-, or 4-vessel configuration. Skip it if you brew single-infusion styles and want fewer parts to clean.
Q: How much does a hot liquor tank cost?
A: It’s quoted against your configuration rather than list-priced, since size, heating method, and options all vary. Full commercial systems run 50,000–80,000 USD; ask for a quote on a standalone HLT.