How Fix LOTS of Condensation on Range Hood?

[IrondaleBrewing]

For context to what follows, I have a dedicated brewing space that's about 150 sq ft. It's insulated, has a mini-split for heating/cooling, I keep the temp at 68F, and I run a small dehumidifier that keeps the relative humidity in the mid-50% range on average.

Thus far in this new-ish space I've been doing 1-gallon batches and don't see myself moving up to more than 2-gallon batches other than in rare cases where I know I'll need more (brew club potlucks, parties, etc.).

Since I knew I was going to be doing mostly small batches I built things out more or less as you would a small kitchen and installed a typical kitchen range hood (a Cosmo 63175S to be exact).

The issue I'm running into is during the boil I'm getting quite a lot of condensation on the range hood, to the point where I have to keep wiping it off every few minutes to keep it from building up and dropping back into the kettle (and also occasionally causes the control panel on the hood to freak out). I run the range hood with a window at least partially open to make sure I have some makeup air and overall good airflow.

Photo for context (excuse the mess of wires on top of the fridge; cable management is on my list!):

The distance between the countertop of the bottom of the hood is 32", which puts the distance between the top of the Gigawort and the bottom of the hood at about 12".

Here's another photo with a 2-gallon pot on a small induction burner for additional context -- the distance between the top of that pot and the bottom of the hood is about 20", and I have the same condensation issue when I use this setup.

I've verified insofar as I can that the range hood is installed and vented correctly, meaning I can see steam getting pulled into the range hood, I don't get moisture in the rest of the room at all, and when I check the vent on the roof I can feel air flowing out. Also this is a one-story building so the distance between the ceiling of the room and the vent isn't far at all.

So my main question is, have other indoor brewers run into this, and if so how did you address it?

I can't imagine this is just the way it is and I have to deal with it, so at this point the options I'm thinking through are:

1. Despite my basic checking, the range hood isn't installed correctly or otherwise isn't working properly -- get it checked out by an appliance repair person/installer (we DIYd this install with help from our electrician).
2. Insulate the ducting so there's less condensation happening up in the range hood and ducting given the temperature differential.
3. The range hood is too low given the height of the kettles -- re-install range hood higher.
4. This particular range hood sucks -- get a better range hood.
5. Range hoods suck in general for dealing with this much steam -- get a condensation hood (if they even make one for a 30" space).
6. Some combo of the above.

Or perhaps there's some other solution entirely.

As a point of comparison, my wife sometimes has things boiling for longer than an our in our kitchen in the house and there are no condensation issues in there, so I'm hoping this is a solvable problem. (Not a totally apples-to-apples comparison given the range hood in the house is nicer, it's rear-vented as opposed to top-vented, and the distance between the top of the pot and the bottom of the hood is much greater, but still.)

I appreciate any experience anyone has with this issue and any thoughts or suggestions people have.

Thanks!

 

[mac_1103]

Can't see the photos. Just file names.

 

[IrondaleBrewing]

Can't see the photos. Just file names.

Odd, they show up fine for me both on a computer and on my phone. Attaching the same photos to this reply to see if that works better.

 

[mac_1103]

Now I can see them in both posts. Weird. Anyway, I don't think the problem is that the hood is too low. If anything it might be too high.

 

[Deadalus]

It's listed at 380 cfm. That's a pretty good amount since you are brewing small batches.

Take the grease screens out, they are unnecessary (save them). They interupting the flow. Insulating the ducts might help a little too.

 

[Deadalus]

Also, if it doesn't go straight up, fewer bends with less sweep are better. For instance, if the ductwork needed an offset, using two 45s vs 2 nineties to make the offset lessens the resistance.

 

[doug293cz]

https://www.homebrewtalk.com/threads/boil-kettle-condenser-no-overhead-ventilation-needed.636955/
Brew on

 

[Bobby_M]

I'm sorry to say that I've noticed a consistent trend where people call me and ask about steam control. I tell them about steam condensers and warn against trying to vent due to condensation like above, noise, expense, etc.....

......a few months later.....

Yeah, I didn't take your advice the first time. Do you think the condenser will really solve my problem?

 

[IrondaleBrewing]

Also, if it doesn't go straight up, fewer bends with less sweep are better. For instance, if the ductwork needed an offset, using two 45s vs 2 nineties to make the offset lessens the resistance.

Thanks -- in this case it's a straight shot to the roof but that would have been a good thing to check for sure.

 

[IrondaleBrewing]

It's listed at 380 cfm. That's a pretty good amount since you are brewing small batches.

Take the grease screens out, they are unnecessary (save them). They interupting the flow. Insulating the ducts might help a little too.

Thanks! I'll give it a shot without the filters and see if that helps. Appreciate the suggestion!

 

[ZapperMike]

I put a double ply of paper towel across the hood fan grates and hold the ends with magnet clips when I brew. It still allows air flow but displaces the water and keeps it from getting into the kettle. Works for me!

 

[WesBrew]

Steam condenser is way to handle it. Buy one or build one, add it to the kettle. I brew 5-10g batches in the house, Zero issues while using one.

 

[IrondaleBrewing]

I'm sorry to say that I've noticed a consistent trend where people call me and ask about steam control. I tell them about steam condensers and warn against trying to vent due to condensation like above, noise, expense, etc.....

......a few months later.....

Yeah, I didn't take your advice the first time. Do you think the condenser will really solve my problem

Steam condenser is way to handle it. Buy one or build one, add it to the kettle. I brew 5-10g batches in the house, Zero issues while using one.

Thanks, I'll look into this. My issue is I use different kettles based on batch size, and honestly in some cases "just cuz," so I may have to give up some of that flexibility. Appreciate the input.

 

[tracer bullet]

You could try perhaps to heat the hood, if it's warmer it would be less likely to condense. Or think of a way to provide a channel to collect condensation and a drain line.

After the latter you're sort of making a steam condenser. Agreed to hit BrewHardware to just do it and get it over with.

 

[IrondaleBrewing]

You could try perhaps to heat the hood, if it's warmer it would be less likely to condense. Or think of a way to provide a channel to collect condensation and a drain line.

After the latter you're sort of making a steam condenser. Agreed to hit BrewHardware to just do it and get it over with.

Thanks -- the other thing I'm going to try because my curiosity is killing me, is take my same pot and boil a couple of gallons of water for an hour on my kitchen stove in the house and see if I get condensation in there. My hypothesis is that I won't, but I'll find out later today. If I don't then I'll be left wondering what the difference is.

 

[DuncB]

You'll faff about with all kinds of tricks to try and stop that condensation.
But anytime the hood and piping is cooler than the steam the vapour will condense.
In a way you already have a condenser!
But all my issues were solved with a condenser on my brew kettle.
No condensation.
Quieter.
Less energy used on the boil.
Recycle the warm water if you are inclined.

 

[mac_1103]

anytime the hood and piping is cooler than the steam the vapour will condense

Right. You rarely get condensation on a kitchen hood because kitchen hoods are warm from all the cooking that's going on right below them. The lack of condensation doesn't necessarily mean the hood is doing a bang up job. In the winter I sometimes get condensation on my kitchen windows while cooking but never on the microwave/hood.

 

[Deadalus]

You mentioned only making 1 gallon batches currently and aren't planning beyond 2 gallons. What size is your total pre-boil volume and how much boil off do you have? Also you said your kitchen is rear vent. Do you mean it goes out the side wall of the house? I target a gallon/hour as my boiloff for a 6 gallon batch. I'm thinking you might be just boiling off no more than a quart for a one gallon batch?

Make sure your kitchen range filters are clean if testing. Condensation is actually how I notice mine are dirty as either the grease clogs my filters or perhaps they are hydrophobic(?). And they are generally not particularly dirty just a little yellow. I used to work in a steakhouse kitchen. We had to take them down every night to run through the dishwasher and they were way dirtier after just one day!

One more thought. You did say that you can feel the air coming out but do you perhaps have any kind of weighted self closing flap? There's usually something to discourage animals from entering. I have one on my wall vent but not sure if they would put one on the roof. Mine works fine but sometimes they don't.

 

[Deadalus]

Your product manual is here. It says a 24" minimum from the stove top to the bottom of the hood. It notes the need for a damper and if you have a damper on the roof or wall not to use the one that came with it. Also there is language in there regarding a thermal break for cold weather and it has specific positioning as far as the damper. I don't know what a thermal break would be here. I do wonder if perhaps you have two dampers on it.

You aren't boiling anything much different than cooking normally given your batch size and you have a decently rated range hood. At the Home Depot site, there was even a homebrewer who gave it five stars.

 

[gaviga]

You'll faff about with all kinds of tricks to try and stop that condensation.
But anytime the hood and piping is cooler than the steam the vapour will condense.
In a way you already have a condenser!
But all my issues were solved with a condenser on my brew kettle.
No condensation.
Quieter.
Less energy used on the boil.
Recycle the warm water if you are inclined.

Any condenser recommendations? I have a similar setup to the OP and am considering adding a condenser, too.

TIA

 

[tracer bullet]

BrewHardware has a setup, @Bobby_M here, he'll probably see this. The gist on them all is the same, and there are options, but he may be able to provide customized details depending on your setup and lid and such.

 

[Velnerj]

The cheapest and easiest option is to reduce the boil vigor and boil time, adjust recipe accordingly.

Brewing such small batches would require mere ounces of additional malt and a gram or two of hops.

There's no reason you need to boil for 60 min at rolling boil, when 30 min at a simmer will do just fine.

 

[DuncB]

I made my condenser, you need a well fitting lid and clamps to hold it on.
Then selection of triclamp pieces that will allow overhang.
Have a look at the thread mentioned earlier in post 7, plenty of examples of different ways to make your condenser.
There are links to short circuit brewing making a condenser as well.
Key point is to ensure a slope towards outflow so that condensation or water spray doesn't run back in to the kettle.
I don't believe there is a Venturi effect from the water spray that causes the pressure to be lower in the kettle space.
Many will disagree probably the pressure is slightly higher in the sealed kettle / boiler and hot things rise hence going out of the tubing.
The system is not sealed enough for low pressure generation. But the direction of water jet promotes the flow along the tube like throwing sticks onto a flowing stream.
It should not be an expensive project at all.
Custom kit looks very good but at my distance it wasn't an option.

Any condenser recommendations? I have a similar setup to the OP and am considering adding a condenser, too.

TIA

 

[tracer bullet]

You aren't boiling anything much different than cooking normally given your batch size and you have a decently rated range hood.

I like this line of thinking. We aren't talking 6 gallons at a roiling boil, it seems that for these smaller batches the hood should be keeping up. Something else could be at play.

 

[Bobby_M]

I don't believe there is a Venturi effect from the water spray that causes the pressure to be lower in the kettle space.
Many will disagree probably the pressure is slightly higher in the sealed kettle / boiler and hot things rise hence going out of the tubing.

It's not a venturi effect at all. The process of condensation reduces pressure. It's the basis for this kind of thing:

If a steam condenser equipped kettle leaks steam out of the lid:
1. The condenser spray volume or temperature is not effective enough for the amount of steam being generated....or another way to say it
2. The amount of steam being generated is overpowering the condenser.
3. The path for the steam to exit via the lid is the lesser resistance than the port into the condenser.

 

[DuncB]

@Bobby_M
Glad you agree not a Venturi effect.
The condensation outcome you show in the picture is in a closed system. It would also occur if no steam in the system at all and that stainless steel vessel was just sealed with very hot dry air in and cooled. Our condensers are working in a system that is open more analogous to a chimney.
Steam does not rise up a chimney or come out of a boiling kettle spout because of condensation.
The steam will always go the way that physics dictates and if your lid isn't sealed that's a prime escape route.

 

[lonetexan]

@Bobby_M
How tight does the lid have to be on the kettle to make this work properly?

 

[WesBrew]

The lid doesn’t necessarily need to be tight, just covered. I use a poorly fitting lid I bought for my kettle. No problems. Make sure to open the lid away from you while adding hops !

 

[tracer bullet]

@Bobby_M
How tight does the lid have to be on the kettle to make this work properly?

I have an Anvil Foundry and I actually leave the hole in the lid open, the hole where the recirculation pipe normally goes through. It's a "just in case" somethign happens I don't create crazy vacuum or pressure in it. The condenser works well enough that no steam ever actually comes out of that hole.

 

[Bobby_M]

@Bobby_M
Glad you agree not a Venturi effect.
The condensation outcome you show in the picture is in a closed system. It would also occur if no steam in the system at all and that stainless steel vessel was just sealed with very hot dry air in and cooled. Our condensers are working in a system that is open more analogous to a chimney.
Steam does not rise up a chimney or come out of a boiling kettle spout because of condensation.
The steam will always go the way that physics dictates and if your lid isn't sealed that's a prime escape route.

I know implosion is from a closed system but the cause is the same. Rapid contraction of volume due to condensation. There is definitely a low pressure created inside the condenser chamber. While it's open to both the kettle and the waste outflow hose, there is less resistance to flow through 1-3/8" bore than 1/2" and the pressure inside the kettle is higher than ambient.

I don't know what else to tell you. When the condenser is running, no steam leaks out of tiny gaps around the lid. When the condenser is not spraying, steam does leak out. Nothing about the steam's ability to escape the via the TC piping changes, just the condensation is happening or not happening.

 

[SBENCIV]

I also struggled with condensation at one point. I had installed a bathroom fan in my brewcave mistakenly thinking this would be more than adequate. Of course, it wasn't. I had water dripping from all the pipes, ceiling, you name it. Then I came across a picture of someone who used semi-rigid ducting, attached to a vent, that was then positioned directly over the kettle. With a little tinkering, I was able to make the same modification and bam! Problem solved! I actually can't believe how well it works. I can brew in my brewcave (located in my basement) and it doesn't even move the needle on the level of humidity in my basement. It works incredibly well! Pic attached. I've used this setup for almost 4 years now and I haven't looked back.

 

[Clint Yeastwood]

This is an amazing thread. I live in Northern Florida, close to Central Florida, and it gets pretty nasty in the summer. I have never had any kind of condensation problem. I don't even run the range hood. I brew in a Braumeister on my kitchen table.

What am I doing right? No idea.

I used to brew in Miami (spit). I don't recall having condensation there, either.

 

[day_trippr]

Extraordinary. I'd think with all the humidity extant having a steaming kettle would bath everything in "sweat"...

Cheers!

 

[Clint Yeastwood]

I wonder if high ceilings and an open kitchen design make the difference.

 

[day_trippr]

Probably some effect there wrt dilution of the humidity below the condensation point, vs boiling in a more confined space...

Cheers!

 

[Clint Yeastwood]

I also have AC on most of the time.

 

[day_trippr]

Big help I'm sure, especially if you have the tonnage to keep up with your kettle

Cheers!

 

[k-daddy]

I understand the concern with condensation dripping onto the control panel but what's the potential harm of a small amount of condensation falling back into the kettle?

 

[tracer bullet]

I understand the concern with condensation dripping onto the control panel but what's the potential harm of a small amount of condensation falling back into the kettle?

Bringing in unwanted flavors. The material of the ductwork, metal or plastic for example. Dust and dirt and anything else in there.

I can't promise you'll notice it or not in the final product, given how diluted the condensation would be. But I somewhat bet that if you were to collect the condensation and drink it, you'd taste things you don't like.

If the duct acts as a steam condenser, at a minimum I'd want to figure out how to collect it and run it to a drain or a bucket.

 

[k-daddy]

Bringing in unwanted flavors. The material of the ductwork, metal or plastic for example. Dust and dirt and anything else in there.

I can't promise you'll notice it or not in the final product, given how diluted the condensation would be. But I somewhat bet that if you were to collect the condensation and drink it, you'd taste things you don't like.

If the duct acts as a steam condenser, at a minimum I'd want to figure out how to collect it and run it to a drain or a bucket.

Thanks. My makeshift garbage can lid hood/fan/ductwork are clean and only used for beer brewing. Condensation only occurs on the edge where the hood meets the duct so I can't imagine I'm exposing my wort to any off flavors from a few ml's of water falling into 7 gallons of wort. It might be a different story if my kettle was sitting under a greasy kitchen exhaust fan.