RAPT fridge...I bought 1....Review

[GrumpyPaul]

MODERATOR COMMENT:

Please keep in mind that this thread is about a review of the RAPT fridge.

The discussion of its pros and cons is welcome - and encouraged. But we are treading very close to the line of this thread slipping into one of the terrible shitstorms that just becomes unproductive.

Keep comments on track about the good and bad about the RAPT fridge (or other RAPT products), point out flaws, make suggestions to improve it, discuss the risk associated with being and "early adopter" of v1.0 of a product etc etc.

BUT - comments that get off track and start talking about the manufacturer, or an other company, and start to steer this thread into one of our famous "I hate/love KK/KL and everything and everyone associated with them" threads wont be tolerated.

Keep the thread on track

 

[Reg Holt]

MODERATOR COMMENT:

Please keep in mind that this thread is about a review of the RAPT fridge.

The discussion of its pros and cons is welcome - and encouraged. But we are treading very close to the line of this thread slipping into one of the terrible shitstorms that just becomes unproductive.

Keep comments on track about the good and bad about the RAPT fridge (or other RAPT products), point out flaws, make suggestions to improve it, discuss the risk associated with being and "early adopter" of v1.0 of a product etc etc.

BUT - comments that get off track and start talking about the manufacturer, or an other company, and start to steer this thread into one of our famous "I hate/love KK/KL and everything and everyone associated with them" threads wont be tolerated.

Keep the thread on track

As you have posted under my last post, am I right that you are suggesting I am trying to start a KL/KK thread? I am just carrying on the general flow of the posts. I can't see anywhere where the thread has gone off track....

 

[GrumpyPaul]

As you have posted under my last post, am I right that you are suggesting I am trying to start a KL/KK thread? I am just carrying on the general flow of the posts. I can't see anywhere where the thread has gone off track....

@Reg Holt

Nah, the fact i posted directly after you was just that i hadn't been on for a few days... most of the threads i alluded to are a few posts back.

In fact most of the posts discusding RAPT are good. Yours in particular i dont have any issue with.

Just felt like the tone of some were heading down that old path and felt it was better to nip it in the bud.

 

[Reg Holt]

Well you are seeing more than me, never saw Keg King mentioned once, as for criticism of Keg Land I think it has been fair. They get a right to reply which they have done, I think it would pay to remember Keg Land exists to serve the brewing community not the other way around. Which it often seems on here.

 

[philrob]

OK, points made about all this, although I'll admit I deleted a post a couple of days ago as I thought it was off track and not helpful to any debate.
Let's now just keep it on track as GrumpyPaul suggested very kindly. There is no criticism of any member and no one has been given any warning points or been banned. Debate as GP suggested is helpful and what this forum is about.

 

[Grmblz]

WTF! is a "warning point?" I've got a couple of comments but given the Draconian direction this forum has taken of late I'm concerned that "free speech" in the Australian context, will be considered high treason and my log in "banned" after all Texas has just made another great leap backwards in personal freedoms has it not? and where do you take your guidance from?
fwiw phil, weal answered a question put to him by kl, how was that "off track?" and deleting that post WAS! a criticism, AND! censorship.
"Debate as GP suggested is helpful and what this forum is about" So why would you want to censor it? Like it or not phil you're coming across as a kl fan, that may not actually be the case, but if it walks like a duck and quacks it sure as hell aint a chicken.
I had the rather dubious honour of being "banned" from both kk and kl threads, my bona fides for equal debate/criticism, (since reinstated to kk, such is the character of those there, yeh ok you may have had a point) no such recognition from the red team alas, even though they implemented my suggestions, which truly shows the calibre or lack thereof of a particular person, but at least saved how many? from the kl v.1 syndrome, not that kl gives a rats rofl.


btw, you do realise that anyone "following" a thread gets the post, even though you've deleted it.
By all means redact any part of this post you're not happy with (that's possibly what you signed up to do) but don't just blanket "delete" cus that's not why we're here, and your affiliations real or imagined should have no bearing on the substance of this debate.

 

[Stoichiometrist]

We do have the manual online here:
RAPT Quick Start Guide - Manual

A quick start guide is not a manual.

The guide was useful to get the unit started / connected but that is all.

it is otherwise bereft of essential information.

 

[Stoichiometrist]

Having used the product for a while now the probe extension in my opinion is not necessary. Some customers are obsessed with using a probe that goes into a thermowell however as the fan in this fermentation chamber is quite powerful the air space in the fridge is very even and fairly quickly the air temperature inside the fridge will be equal to the core temp in the fermenter. So you really do not need to use the extended probe and the included one on the side of the fridge does a perfectly adequate job.

If you guys really wanted us to do this would could make the extended probe come as standard but we are also a bit worried that some customers may find that this looks a bit messy having a new product arrive to you with a long dangling cable that you may or may not want to use. Would be keen to get all your thoughts on this though. How many of you would prefer the neat probe integrated into the wall or to have the long probe pre-installed?

As mentioned earlier I think the extension probe should be mandatory with the unit. At least until you get your other rapt products sorted.

Let the customer decide. I think it would be useful to have community testing to validate which probe type and position works best in this fridge.

Accurate fermentation temperatures is not a new concept. Members have already shared their experiences and opinions. They suggest the best temperature readings are obtained from the liquid and not surrounding air.

I am sorry but I simply do not believe your statement:

‘the fan in this fermentation chamber is quite powerful the air space in the fridge is very even and fairly quickly the air temperature inside the fridge will be equal to the core temp in the fermenter’

I think you need to provide proof to make a statement like this.

Scientifically it’s ridiculous. There’s no fan (agitator) in the liquid so there’ll be a temp gradient. Plus fermentation is an exothermic reaction.

It’s certainly not my experience. For my latest batch, I’ve got two additional temp probes on the side of the fermenter. To achieve temps between 18-20 degrees I’ve had to set the rapt thermostat to as low as 11 degrees and max 16 degrees.

You should put this in the manual if you ever release one.

 

[mynameisrodney]

Scientifically it’s ridiculous. There’s no fan (agitator) in the liquid so there’ll be a temp gradient.

The yeast itself does a pretty good job of agitating the fermenting beer, I doubt there's a significant temp gradient in the beer during active fermentation, and the flow across the wall of the fermenter should be adequate.

It’s certainly not my experience. For my latest batch, I’ve got two additional temp probes on the side of the fermenter. To achieve temps between 18-20 degrees I’ve had to set the rapt thermostat to as low as 11 degrees and max 16 degrees.

Out of curiosity is this with the fan on or off? I know the last advice from KL was to have the fan off when not heating or cooling, but this to me seems like a good way to get overshooting on the hot side.

As mentioned in a previous post, if it were me, I'd disable heating until you want to raise the temp for a diacetyl rest. Fermentation is producing enough heat in an insulated chamber at this time of year, you shouldn't need to add more. That plus fan on constantly and track the fermenter temp separately as you are doing now and see how it goes.

 

[Stoichiometrist]

The yeast itself does a pretty good job of agitating the fermenting beer, I doubt there's a significant temp gradient in the beer during active fermentation, and the flow across the wall of the fermenter should be adequate.



Out of curiosity is this with the fan on or off? I know the last advice from KL was to have the fan off when not heating or cooling, but this to me seems like a good way to get overshooting on the hot side.

As mentioned in a previous post, if it were me, I'd disable heating until you want to raise the temp for a diacetyl rest. Fermentation is producing enough heat in an insulated chamber at this time of year, you shouldn't need to add more. That plus fan on constantly and track the fermenter temp separately as you are doing now and see how it goes.

Hi Rodney. Yep, fan off as directed by KL. Heating disabled.

True, the fermentation / co2 release is an agitator.

But I’ve not observed such a discrepancy between temp measures with previous batches (Inkbird and other probes used concomitantly). I’ve never used a keezer before cos I saved all my $ for the ‘Plug and Play’ RAPT fridge. I’d be interested in the experiences of other members with ‘off the shelf’ fridge/freezers.

I’m surprised that I have had to run the fridge at 11-16 degrees to achieve 18-20 at the surface of the fermzilla all rounder. Note, starting temp was 19.5 degrees.

KL and others made a point about the energy required to heat volume of air vs water. There was also a KL comment about the temp always remaining between the hysteresis points. That’s not my experience, when you look at the graph I previously posted.

The explanation by KL in my mind highlights the problem. Because the thermal mass of air is small it takes very little effort for the (very industrial sounding heater and cooler) to achieve the set temperature in the AIR. But, based on my observations, this is not translating to achieving the desired temperature in the LIQUID. Which is the critical factor.

The tiny amount of energy added to the system by cooling/heating the air to the set temp is far less than what is required to achieve the desired effect in the liquid- and the cycle continues as the temperature swings wildly.

I’m not an engineer or scientist so I’m keen for people with knowledge / experience in this to chime in.

Perhaps the rapt needs a second small, quiet fan to run when the cooler / heater is not on?

 

[Stoichiometrist]

WTF! is a "warning point?" I've got a couple of comments but given the Draconian direction this forum has taken of late I'm concerned that "free speech" in the Australian context, will be considered high treason and my log in "banned" after all Texas has just made another great leap backwards in personal freedoms has it not? and where do you take your guidance from?
fwiw phil, weal answered a question put to him by kl, how was that "off track?" and deleting that post WAS! a criticism, AND! censorship.
"Debate as GP suggested is helpful and what this forum is about" So why would you want to censor it? Like it or not phil you're coming across as a kl fan, that may not actually be the case, but if it walks like a duck and quacks it sure as hell aint a chicken.
I had the rather dubious honour of being "banned" from both kk and kl threads, my bona fides for equal debate/criticism, (since reinstated to kk, such is the character of those there, yeh ok you may have had a point) no such recognition from the red team alas, even though they implemented my suggestions, which truly shows the calibre or lack thereof of a particular person, but at least saved how many? from the kl v.1 syndrome, not that kl gives a rats rofl.


btw, you do realise that anyone "following" a thread gets the post, even though you've deleted it.
By all means redact any part of this post you're not happy with (that's possibly what you signed up to do) but don't just blanket "delete" cus that's not why we're here, and your affiliations real or imagined should have no bearing on the substance of this debate.

Question:

Do you think the comment made by WEAL in hisreply that was deleted was relevant to this thread and/or was meant to be inflammatory?

WEAL acknowledges this comment was the reason why his post was removed in post #57.

I”d really like to continue a constructive conversation with out the hyperbole. Cheers

 

[mynameisrodney]

But I’ve not observed such a discrepancy between temp measures with previous batches (Inkbird and other probes used concomitantly). I’ve never used a keezer before cos I saved all my $ for the ‘Plug and Play’ RAPT fridge. I’d be interested in the experiences of other members with ‘off the shelf’ fridge/freezers.

I’m surprised that I have had to run the fridge at 11-16 degrees to achieve 18-20 at the surface of the fermzilla all rounder.

Yeah that's no good. If you haven't seen that discrepancy with previous batches, and this is the first one with the fan off, then that points to the fan off as the culprit.

KL made a point about the energy required to heat volume of air vs water in an attempt to explain that everything is fine.

But it’s not fine. And the explanation by KL in my mind highlights the problem. Because the thermal mass of air is small it takes very little effort for the (very industrial sounding heater and cooler) to achieve the set temperature in the AIR. But, based on my observations, this is not translating to achieving the desired temperature in the LIQUID. Which is the critical factor.

The tiny amount of energy added to the system by cooling/heating the air to the set temp is far less than what is required to achieve the desired effect in the liquid- and the cycle continues as the temperature swings wildly.

What they said was that wild swings in the air temp are to be expected, and this is true. When the fridge switches on the air will rapidly cool to below the set point and turn off. As you say, the thermal mass of the air is tiny compared to the thermal mass of the beer, so these wild temperature swings are not necessarily occurring in the beer. Cycling this on and off to get to the desired temp of the beer is a valid approach. It's similar to cycling a heating element off to keep a desired mash temp. There's no point in worrying about the heating element rapidly changing temp as it switches on and off, what matters is the mash temp.

Missing the setpoint is a different issue. Maybe it helps to split the problems out and address individually.

1. The air temp rapidly fluctuates. In my opinion this doesn't matter as long as the beer temp is stable, and the fluctuations aren't so quick that you are damaging equipment with rapid cycling. EDIT: AND as long as the "up" swings are as a result of the beer heating the air and not the heater heating the air.
2. The beer temp is way off the target temp. Very much an issue. As mentioned I'd turn the fan back on and see if you are closer to target.
3. The unit is inefficient due to heating then cooling then heating etc. Real issue, but likely due to incorrect setup (due to lack of user manual). Only in the dead of winter do I need to use a heater, definitely not in October. Turn off the heating element, this will make it more efficient, and slow the temp cycling in the up direction.
4. The beer temp is fluctuating too much. I don't think we can address this until the above are correct. My gut says that you wont see wild fluctuations.

 

[duncbrewer]

FWIW
ferment fridge, with a Fermentasaurus in, heat belt, brewpiless, probe on outside just under some insulation at the " stand height " on the FS and a probe measuring air temp. Supplementary Ispindel ( so floating higher than the beer temp probe is positioned ).
I see a tiny variance in beer temp during active ferment between the spindel and the beer probe ( at different heights). After ferment is over variance less than half a degree. I don't have a fan running all the time the only fan occurs when cooling is enabled and this is in the freezer compartment that ducts down into the fridge to add supplementary chilling. Picture of the fridge freezer and the hole that has duct from freezer fan connected to move the really cold air. The room is about 22 celsius today.


Brewpiless data the last several hours

Beer temp green line, Blue line Fridge temp, Beer set to 1 celsius is a red line but also has some orange line overlaying on it which is fridge set temp.
Blue blocks across bottom are the time the cooling is in action. The Ispindel only takes readings every half an hour but they have been between 0.44 celsius and 0.75 celsius across this time frame. So cooler beer nearer the cooled blast of cold air..
I'm pretty happy with this variance.

 

[Stoichiometrist]

Thanks again Rodney. Heating disabled before starting this brew.
Yep I was thinking of turning fan on full time and see what difference it makes. Although the fermentation is slowing down now so there be less heat generated now too - potential confounding factor.

 

[Grmblz]

Question:

Do you think the comment made by WEAL in hisreply that was deleted was relevant to this thread and/or was meant to be inflammatory?
Given that he was answering a question put to him by someone from kl I would say yes to relevant, as to the wisdom of mentioning ongoing legal issues that's a different issue which he has acknowledged.

WEAL acknowledges this comment was the reason why his post was removed in post #57.
That's my point, the whole post was deleted because of one questionable comment in it, why not redact that one comment and let the rest of the answer stand?

I”d really like to continue a constructive conversation with out the hyperbole. Cheers
Hyperbole: "exaggerated statements or claims not meant to be taken literally" Care to share some insight as to which parts of my post are hyperbole?

I currently operate 3 fermentation chambers, actually 4 if you include the cheese maker which like my egg incubators is humidity controlled as well as temp, so I have a reasonable idea of what does and doesn't work.
As you correctly surmised in #68 they are full of shiv, #30 and #35 are complete and utter nonsense, and cycling on and off almost constantly probably wont hurt the heater, but the compressor wont like it, and neither will your electricity bill, but I think you've already worked that out.
I understand that after buying into the whole "RAPT is great" thing, you are disappointed that it doesn't live up to your expectations, but it is what it is, and you can cut your losses and sell it while there's still a market for it (given the hype around the thing you could probably make a profit then wait for V.2 or V.3, alternatively have a good read of page one of this thread, the information there will at least render it usable.

 

[Stoichiometrist]

I currently operate 3 fermentation chambers, actually 4 if you include the cheese maker which like my egg incubators is humidity controlled as well as temp, so I have a reasonable idea of what does and doesn't work.
As you correctly surmised in #68 they are full of shiv, #30 and #35 are complete and utter nonsense, and cycling on and off almost constantly probably wont hurt the heater, but the compressor wont like it, and neither will your electricity bill, but I think you've already worked that out.
I understand that after buying into the whole "RAPT is great" thing, you are disappointed that it doesn't live up to your expectations, but it is what it is, and you can cut your losses and sell it while there's still a market for it (given the hype around the thing you could probably make a profit then wait for V.2 or V.3, alternatively have a good read of page one of this thread, the information there will at least render it usable.

Argh you might be right Grmblz. But I hope not.

Thanks duncbrewer. Nice set up.
I’ll post a pic of the latest graph when I can.

 

[mynameisrodney]

Don't give up hope. Take another look at duncbrewer's post. He has a setup that he is pretty happy with, and there's a few important bits of useful info there:

1. His beer temp swing is only around half of his air temp swing.
2. His graph is zoomed WAY in compared to yours. Check the cycle times and not just what the graph looks like. His is about 2h30m between compressor cycles. Yours looks to be ~1h45m from Oct 2-6 when cycling quick and ~3h after Oct 6 when you changed the hysteresis back to 2C. So you are in the same ballpark there.

 

[wide eyed and legless]

Question:

Do you think the comment made by WEAL in hisreply that was deleted was relevant to this thread and/or was meant to be inflammatory?

WEAL acknowledges this comment was the reason why his post was removed in post #57.

I”d really like to continue a constructive conversation with out the hyperbole. Cheers

I agree with you, the comment I made is relevant, (to the stock situation) but deserving of its own thread.

 

[duncbrewer]

Thanks @Stoichiometrist and @mynameisrodney
Just to show it's fairly consistent and reminding me to go and put some finings in the Saison so it's ready for transfer at the weekend and I've got room for the next ferment.

 

[Stoichiometrist]

I agree with you, the comment I made is relevant, (to the stock situation) but deserving of its own thread.

I am glad you agree that your comment was inflammatory.