Profitec Pro 700 Brew Temperature Stability

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BigSteam
Posts: 6
Joined: 8 years ago

#1: Post by BigSteam »

Hi all,

I've had my Profitec Pro 700 for about 2 weeks now and I'm very much enjoying it. However, I have a question regarding the displayed brew PID temperature after pulling a shot.

Usually when I pull a shot the brew boiler will drop a max of 1-2 degrees C. However I've noticed on occasion that it will drop significantly further. For example, this morning I pulled a 25 second shot with the brew boiler set to 94 (offset remains unchanged, which I think is 14C), and once the timer flashed off the brew boiler was displaying 89 degrees. Is this normal?

Thanks

spearfish25
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Joined: 9 years ago

#2: Post by spearfish25 »

Without knowing anything more, I'd say normal. Things that impact the temp change during a shot include the temp stability of your machine and the flow of your shot. I notice that if I haven't allowed my machine to warm up fully, I don't have the extra thermal mass to maintain the brew temp. After a shot it will read lower temps than if I let the machine warm up a solid hour. Second, faster flowing shots pull more water into the boiler and cool it more quickly. Compare the temp deltas to your brew ratios and you'll notice that a 34s ristretto will have a final brew temp nearly identical to the starting temp. A lungo or a flush of the group will drop the temp considerably.
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Alex
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HB
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#3: Post by HB »

BigSteam wrote:For example, this morning I pulled a 25 second shot with the brew boiler set to 94 (offset remains unchanged, which I think is 14C), and once the timer flashed off the brew boiler was displaying 89 degrees. Is this normal?
Sorry, I didn't pay particularly close attention to the readout during the review of the Pro 700.

With most PID-controlled espresso machines and especially non-commercial ones, the temperature reading is only meaningful when the machine is idle. This is because of differences in boiler size, preheat or not, and particularly the placement of the temperature probe. The reading may change dramatically once the pump starts and cool water enters the boiler. Some manufacturers take advantage of this and intentionally place the probe near the water inlet so the PID will react more rapidly (e.g., Quickmill Alexia). As I noted in the review research, the Pro 700 has very good temperature stability.
Dan Kehn

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SonVolt
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#4: Post by SonVolt »

Mine follows this behavior - sometimes it only drops a few degrees then bounces back almost immediately. Sometimes it drops 10+ degrees. Also, I battled sourness until I bumped the boiler temp up to 202F.

Todd Salzman
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#5: Post by Todd Salzman »

Yes, that drop in temperature is normal. Sometime the cold water coming in can affect the sensor and show a lower temperature than the boiler actually is. But the good new is that there is enough mass in the boiler to keep your actual brew temperatures stable for that coffee and your next. So there is nothing to worry about.
Todd Salzman
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jonr
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#6: Post by jonr »

Espresso machines are almost always repeatable. Ie, under the exact same conditions, it will behave the same way again. You might get more consistency out of the machine by understanding what conditions effect it. Room temp, source water temp, shot volume, warm-up time, etc.

BigSteam (original poster)
Posts: 6
Joined: 8 years ago

#7: Post by BigSteam (original poster) »

Thanks for the replies everyone. Some additional information: the machine is on a timer and turns on an hour and 15 before I start making my first espresso. Secondly, current ambient temperature is around 25 C so not exceptionally cold.

I think I've found the issue. Usually I use the brew water to preheat the group and cup (lift the lever for approx 4-5 seconds). However I've noticed that after doing this the PID doesn't measure the temperature drop in the brew boiler for maybe 15-20 seconds, then the temperature will drop from the set point quite slowly before rising again. This led me to believe the brew boiler had recovered from the flush when it hadn't.

This morning I deliberately took longer between heating the cup and pulling the shot probably 2 minutes or so. The post brew temperature drop was much less (3 degrees C).

My old machine (Expobar brewtus) had brew water preheat so it's not something I was used to taking into account.

spearfish25
Posts: 806
Joined: 9 years ago

#8: Post by spearfish25 »

I just made my routine to heat cups with the hot water wand before doing anything. Then grind and pull shot and steam milk. The time between cup warming and shot pulling is usually plenty for the steam boiler to recover.
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Alex
Home-Barista.com makes me want to buy expensive stuff.