How to Descale a Bunn Coffee Maker (Speed Brew, Velocity Brew, My Café)

Two Bunn Manuals, Two Different Soaks

To descale a Bunn Speed Brew, pour 1 quart of white vinegar through it, switch it off and unplug it, and let the vinegar sit in the tank for at least 2 hours. Then clean the sprayhead and flush with fresh water three or more times. BUNN calls this "routine cleaning" and asks for it every 3 months. Vinegar is the only descaler its home manuals name.

The details change by model, and BUNN's own manuals disagree on one of them. The Velocity Brew book keeps the brewer plugged in with the vacation switch on during the 2-hour soak, then flushes about 8 to 10 times. The newer Speed Brew book unplugs it first. The Phase Brew, Heat N Brew and single-cup My Café each have a smaller procedure of their own. Find yours below, and follow the manual that came with your machine.

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Which Bunn Do You Have?

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What You Need

Why not a commercial descaler? BUNN's safeguards say not to pour any liquid into the internal hot water tank "other than water or vinegar for cleaning, as specified in this manual". That rules out CLR, citric acid packs and espresso-machine descalers, whatever their labels say.

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Step 1: Set Up the Funnel and Carafe

1. Remove any filter and grounds, then slide the empty brew funnel into its rails.
2. Put the empty carafe under the funnel.
3. Leave the brewer plugged in and switched on as normal. BUNN's procedure only switches it off after the vinegar has gone in.

Time: 2 minutes

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Step 2: Pour in the Vinegar

1. Open the lid and pour 1 quart (32 oz) of white vinegar into the pour-in bowl.
2. Close the lid. On these models, water isn't released into the tank until the lid is closed.
3. Let the brewer run. The vinegar pushes hot water out through the funnel.
4. When the flow stops, empty the carafe.

Time: About 5 minutes

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Step 3: Let the Vinegar Soak

The vinegar now fills the tank and the sprayhead tube, where the lime is. It needs time to dissolve it.

Speed Brew (53883.0002): flip the tank switch off and unplug, then leave it for at least 2 hours.

Velocity Brew (43097.0002D01): leave it plugged in with the vacation switch on for 2 hours, then unplug.

Time: 2 hours

⚠️ Safety: whichever version you follow, the tank is full of hot liquid. Don't open anything or move the brewer during the soak.

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Step 4: Clean the Sprayhead and Tube

With the brewer unplugged after the soak, the sprayhead comes off.

1. Slide out the funnel and unscrew the sprayhead with your fingertips.
2. Clear every hole with a toothpick, wash it with dish soap, and rinse it.
3. If the brewer had been slowing down, use the deliming tool on the tube. Insert all but two inches of it into the sprayhead tube and slide it in and out five or six times.

BUNN warns that different models take different deliming tools, so use the one supplied with yours. Our Bunn spray head cleaning guide has the full removal and refitting steps.

Time: 10 minutes
Tools: Toothpick, deliming tool

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Step 5: Flush With Fresh Water

1. Slide the funnel back in, carafe underneath.
2. Pour a carafe of fresh cold water into the pour-in bowl and close the lid.
3. Empty the carafe when the flow stops.
4. Repeat until there's no vinegar smell. That's 3 or more times on a Speed Brew, and about 8 to 10 times on a Velocity Brew, per its manual.

Time: 15-40 minutes

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Step 6: Refit, Power Up, Wait 15 Minutes

1. Screw the sprayhead back on, finger tight.
2. Plug in and switch the tank on (vacation switch on a Velocity Brew).
3. Wait 15 minutes before brewing. That's how long BUNN says the tank takes to reach temperature.

Time: 15 minutes

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Step 7: Check the Result

Brew a pot of plain water. On a Speed Brew or Velocity Brew it should take around 3 to 4 minutes, with nothing left in the pour-in bowl. If any vinegar smell remains, run one more rinse. If the brew is still slow, the deliming tool from Step 4 is the next thing BUNN suggests. Our slow brewing guide has the rest.

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Phase Brew (HT, HG): Deep Clean

The Phase Brew heats each pot in its Top Tank, so there's no always-hot tank to soak. Its display flashes between the time and CLE when a deep clean is due.

1. Take the sprayhead off and clear its holes.
2. Fill with water to the 6-cup (30 oz) mark.
3. Add 2 cups (10 oz) of white vinegar to bring it to the 8-cup mark.
4. Run it through with the On/Off button.
5. Run 2 to 3 fresh-water cycles.

The Phase Brew manual gives no button combination for clearing CLE, so don't borrow the Heat N Brew's.

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Heat N Brew (HB): Clean and Reset

The Heat N Brew shows CLEAN when it needs this, and it's the only BUNN home brewer with a reset combination afterwards.

1. Fill the Top Tank with 25 oz of water and 25 oz of white vinegar, or 50 oz of straight white vinegar.
2. Start a brew, let it heat for about 4 minutes, then pause it with the Brew button.
3. Let it soak for 30 minutes, then restart and let it finish.
4. Run 3 or more fresh-water cycles.
5. With the brewer idle, hold H and M together for 3 seconds to clear CLEAN.

If water ever drips through before heating finishes, the HB manual blames lime on the valve between the Top Tank and the sprayhead. This cleaning cycle is the fix for that too.

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My Café MCU: Single-Cup Clean

The My Café has its own small hot water tank, and its manual asks for this at least every 3 months, more often with mineral-rich water.

1. Insert any drawer.
2. Open the Spin Lid and fill the pour-in bowl with 14 oz of white vinegar.
3. Close the lid, place an empty cup larger than 14 oz under the drawer, and press Brew.
4. Run three or more 14 oz cycles of plain water to flush it.
5. Clean the sprayhead. Unplug and cool for at least 1 hour, then turn it clockwise to remove it, wash it, and refit it counter-clockwise, finger tight.

If the brewer has become louder or the pump keeps running, scale on the two water probes in the pour-in bowl is the likely cause. The manual's fix is in our Bunn error codes and lights guide.

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How the Procedures Compare

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Troubleshooting the Descale

The vinegar smell won't go. Keep flushing. The Velocity Brew manual expects 8 to 10 rinses, so three may not be enough on an older tank.

Nothing came out when I poured the vinegar in. The lid has to be closed before water moves into the tank. If it's closed and the vinegar is still sitting in the bowl, the sprayhead is blocked. Clear it (Step 4) and continue.

The sprayhead won't unscrew. Lime is holding the thread. Finish the soak and rinse, let it cool, and try again by hand. On a My Café, turn it clockwise.

CLEAN is still on after the Heat N Brew clean. Hold H and M for 3 seconds with the brewer idle, not mid-cycle.

Still slow afterwards. Run the deliming tool through the tube. BUNN names it as the next step when cleaning doesn't restore brew time.

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When Descaling Isn't the Answer

Stop and call BUNN if:

• Water appears under the brewer. BUNN's guidance for a leak is to call, and never disassemble the brewer. There are no user serviceable parts inside.
• There's a burning smell, or the breaker trips.
• A My Café's sprayhead seal is cracked or torn. Don't use it until it's replaced.

Warranty: three years on a new Speed Brew, Velocity Brew, Phase Brew or Heat N Brew (glass carafe excluded), and two years on a My Café MCU. Both exclude damage from "use with water having a high mineral content". Regular descaling is part of keeping the warranty valid. Call 1-800-352-2866 (USA) or 1-800-263-2256 (Canada) with the model and date code from the cord prongs, the bottom or the lower back.

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How Often to Descale a Bunn

• Every 3 months: the full vinegar clean, on every home model. That's BUNN's own interval.
• Every 3 months: sprayhead off and cleared. Twice a month in very hard water on a Speed Brew.
• Sooner if: brewing slows, the rumbling won't settle, or CLE / CLEAN appears.
• Before storage, a move or freezing temperatures: drain a Speed Brew or Velocity Brew. Switch off, unplug, cool 2 hours, take off the funnel and sprayhead, and tip it upside down over the sink.

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FAQ

Can I use CLR or a descaling solution in a Bunn?

Not according to BUNN. The home manuals permit only water, and vinegar for cleaning, in the internal tank, and every cleaning procedure uses white vinegar. A different product puts you outside the manufacturer's instructions.

Should my Bunn be plugged in while the vinegar soaks?

It depends on the manual. The current Speed Brew manual says switch off and unplug for the 2-hour soak. The Velocity Brew manual says leave it plugged in with the vacation switch on. Both come from BUNN, so follow the one for your model.

How much vinegar does a Bunn need?

One quart (32 oz) for a Speed Brew or Velocity Brew. A Phase Brew uses 10 oz with 30 oz of water, a Heat N Brew 25 oz with 25 oz of water (or 50 oz straight), and a My Café 14 oz.

Why does my Bunn need so many rinse cycles?

On the always-hot models, each carafe of fresh water only displaces part of the tank, so vinegar dilutes out gradually. That's why the Velocity Brew manual calls for about 8 to 10 flushes, not one or two.

Does a Bunn have a descale light?

Only the clock models. A Phase Brew flashes CLE and a Heat N Brew shows CLEAN. Speed Brew and Velocity Brew have no display, so they rely on the calendar and on brew time. The My Café has no cleaning light either, so use the 3-month interval.

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Related Bunn Guides

• Bunn Spray Head Cleaning Guide: removing and refitting the sprayhead on each model
• Bunn Coffee Maker Brewing Slow?: when descaling is and isn't the fix
• Bunn Coffee Maker Not Heating?: which switch runs the tank
• Bunn Phase Brew Not Heating?: the Top Tank models and their CLE and CLEAN warnings
• Bunn Error Codes and Lights: every code and light BUNN documents

Sources: BUNN Speed Brew Owner's Manual (53883.0002, models GRX/BX/SBS/CSB1/CSB2/BTX/CSB3T); BUNN Speed Brew Owner's Manual (53883.0001A, models BT/CSB/GR/SB); BUNN Velocity Brew 10 Cup Use & Care Manual (43097.0002D01, models NHS/GR/BX/BT/ST); BUNN Phase Brew 8 Cup Use & Care Manual (HT/HG); BUNN Heat N Brew Model HB Use & Care Manual (52774.0000a); BUNN My Café Single Cup Multi-Use Brewer Use & Care Manual (MCU, 43460.0002D).