Rocket Stove - heating/boiling water for brewery

Hello!
I am pretty new to rocket stoves however in typical newbie fashion I have my sights set high for what I would like to achieve with one!
I am aiming to set up a brewery that is fired completely with two(or more) rocket stoves. The fuel would be coppiced willow grown on our land and kiln dried.

Here’s my rough plan:

Rocket stove water heater 1
For the initial part of the brewing process  (hot water is mixed with the grains)

Design based on:
Immersion coil design (similar to this - http://www.permaculturenews.org/images/rocket_water_heater_diagram2.jpg)

What it needs to do:
Raise 200 Litres (42 gal) of water from ambient temperature to 78C (170F) in less than 3 hours.  Water will then be used up in 2 x 100L batches.

Questions:
Will the water ever get that hot in this type of design?
Is it the most efficient way of heating lots of water?
I imagine this is scaleable (as long as temps are reached) whilst the fire burns, and the tap is running?


Rocket Stove Water Heater 2
To boil the beer.

Design based on:
Institutional barrel stove -    

What it needs to do:
Boil 160L (42gal) of beer rigorously for 1 hour.

Questions:
Is this the best design for this?
Is there a limit to how big this design can get? (i realise i would have to make my own drums etc, i.e not a 55gal drum)
What if I wanted to boil 400L (105 gal) of water?


Thanks to all in advance!

D

I've been planning on doing the same. I've got two beer pumps to move the water and wort around but I plan on using two J-tube rockets or two Walker sidewinders under the boil kettle with  diverter plates where the fire will directly hit the pot, One under the Mash tun and one under the hot water tank. I will have the heat wrap around the pot like that one in your video but use a J-tube/sidewinder. The pumps will allow me to use coils through the mash or through the hot water tank depending on what type of grain I'm using. The tanks are open at the top so you don't have to worry about having direct fire on the pots. My plan is to add an electric immersion heater into the hot water tank to keep it at temp once I bring it up with the rocket, after that the pump will help keep the mash at my temperatures. For the boil kettle I will install some sort of paddle that will stir the wort to help prevent scorching. I suppose you could also add a diverter valve so you can take the rocket exhaust or some of it and send it straight to the chimney to help control the temp when it gets too high. I think I'll have to put that into mine.

I think using the tank with the coil will work. You might try using your heat exchanger to pre-heat batch two while cooling down batch one. Then you can heat one batch of hot water and after you use that up you can refill it with the waste heat heated water. That will be my approach, maybe we can compare notes? I'm curious now as to how much each system will use in terms of wood.
I had a beautiful set up in Thailand that we welded from 304. over a one barrel system. But it got stolen before I could ship it back to Bohemia. So back to the drawing board.

Good luck, I am envious, it will be a while before I'll have time to set my system up. I only get to brew when I travel to California.

Jason

Hi Dylan good luck with your brewery.  Beer is good!! (I'm from Oz so I'm biased)

The 1st rocket heater you listed is designed to heat water thats under pressure like in your water pipes at home.  There is an amount of inefficiency in the design thats necessary to avoid the explosions that occur when water is turned to steam in a pressure vessel (known as boom squish)

If you only need to heat 200 lt you can use an open top vessel like you were describing in your 2nd rocket heater.

The general approach of your 2nd heater will work fine but you may like to consider a J tube or even a batch burner.  The batch burner is more complicated to build but generates more heat for a given size.  If these terms are new to you then more reading on Permies and http://donkey32.proboards.com/ will help.  (I just saw that you have found donkey's forum)

These designs can be made as big as you will want so achieving your aim is not at issue but finding the best type and size will affect wood consumption.

You should have a lot of fun with this

Maybe a bit more info would help - what type of brewing setup do you have and what equipment:
3 Tier gravity system of HLT - MLT - Kettle?
Using pumps?
HERMs setup?
Are you planning on using the "rocket stove water heater 1" as the HLT, or setting it up to use as a hot water heater for other purposes in addition to the brewing?
Do you need the 200L all at once for 2 simultaneous batches?

Mat

Hey...

Wow thanks for all the help already!
Jason Learned, sorry to hear about your Thai brew setup being stolen! However your plans for the next one sound pretty epic, and quite technical - I like the immersion heater idea to keep at temps, I am guessing it doesnt use much power to keep temp rather than raise it. And good thoughts on the scorching and valve.  Better book that trip to California

Alan Loy - Thanks man really useful, good to hear from an Ozzie on the subject of beer!  ok I get you, I am familiar with the j-tube but will do some research on the batch burner...do you mean batch box? I just found some very interesting stuff on that - where you can load lots of wood at one...oh and just discovered the P-Channel - time to crank it up a gear and get back to the drawing board

Mat Smith - So yes the plan is to have a 3 tier gravity system - no pumps - no HERMs just Hot Liquor Tank (HLT) - Mash Tun and Boil Kettle.
The plan was to use rocket stove heater 1 as the HLT, so I can have a load of hot water on tap as and when I need it, however it could also be for household use when not brewing?? (not sure yet.)
The 200L is split - 100L for the initial Mash, then another 100L an hour later for the sparge
(so for non brewers that is basically 100L poured on the grain then you let it sit for an hour - Mash, then another 100L poured over the top to rinse the grain - Sparge)
So I could heat 100L then start again and heat another 100L as long as it took less/= an hour, so I had the next 100L ready for the sparge...

What I like about the coil system, if it can reach 78C (170F) is that it is scaleable - so if I decide to make a bigger brewery it still works, as long as i have enough wood!

And if I can increase the boil kettle size too with a batch burner/box it could all start coming together....with lots more research.  Including how much wood do I need to heat X amount of water! Any ideas? Are there any rough calcs out there, or are there too many variables?  I am thinking of growing Willow coppiced and kiln dried...

On a side note: Its funny i went to an old 19th century house today for a visit and in the back courtyard you can see how, back in the day, they made cheese, laundry, bread, salted meat etc AND there was a brewery! There were 2 massive (1000L approx) vats with fires underneath, the fires weren't huge and very simple. Apparently the beer would leave the vats, travel along a long pipe to the cellar (to cool) then get tapped and ferment - but guess what the vats were made of.....LEAD! lovely lead lined brewing pots...yummy! Also lead boxes were used to salt the meat in!

Thanks again guys, beers coming your way if this thing works!

Hey Alan Loy (and others),

I took your advice and looked into designing a j-tube version of the Institutional Rocket Stove. I have looked around for something similar but can’t seem to find anything; most J-tubes and batch boxes seem to be for Mass Heaters not cooking.
See my design here:
https://www.dropbox.com/s/fvuidnz9cxe547i/diagram%2001.jpg?dl=0

As I mentioned I need to boil beer in an open pot for 60-90mins. Ideally I would like to be able to scale up my design to boil quantities of up to 200L at a time. The system here is for a 100L pot (70L) boil so I am looking to double the amount of beer I need to boil.

As you can see the design is a hybrid of an institutional rocket stove (Apravecho research centre) and a J-tube rocket system – hopefully not a total dog’s dinner! I haven’t included any trip wire or Peter Channel yet as first of I am just wondering if the basics of this design are actually going to work. I will be using highly insulative bricks throughout to ensure all of the heat hits the pot and doesn’t get lost on the way.


Questions:

Is this any good? Would it work?

If it might work, what tweaks could I do to improve it? Or have I got it all completely wrong!?

What would be the best way to scale this up to double the size? Could I keep the J-tube the same but make a wider/taller barrel configuration to hold a bigger pot, or would I need to increase the rocket stove itself?

I am using an 8inch (20.3cm) system – do I have the J-tube set up correctly? I have used a 1:2:4 ratio shown by the dotted line.


Thanks

Dylan

Gap C between riser and pot needs to be at least 5 or 6 cm and gap D around the pot probably 2 or 3 cm; and you need a big transition area from the top of gap D to the chimney pipe - ideally a thick donut of airspace that the flue gases can flow easily around and reach the chimney. All of these are to avoid choking the draft. 8" is a pretty big system and I think as big as you want to get.

Depending on the consistency of the beer material you might have issues with overheating and scorching, so keep that in mind as you test and be prepared to add a diffuser plate so the 2000F flue gases don't hit the pot directly. (Water doesn't care of course as it can't scorch )

Glenn Herbert wrote:Gap C between riser and pot needs to be at least 5 or 6 cm and gap D around the pot probably 2 or 3 cm; and you need a big transition area from the top of gap D to the chimney pipe - ideally a thick donut of airspace that the flue gases can flow easily around and reach the chimney. All of these are to avoid choking the draft. 8" is a pretty big system and I think as big as you want to get.

Depending on the consistency of the beer material you might have issues with overheating and scorching, so keep that in mind as you test and be prepared to add a diffuser plate so the 2000F flue gases don't hit the pot directly. (Water doesn't care of course as it can't scorch )

Hi Glenn, sorry I've been away from this for a while, just wanted to say thanks for the reply! Really helpful....

planing on doing something similar...

did you end up building this?

i just upcycled two old pression beer kegs of 50l each

till now i've been doing 25l batches, would like to go up to 200l, so would be ideal to boil/heat two pots at same times...

i thought of J shaped rocket stove like the one in your diagram, and then making somehow a top skirt that envolves both pans, probably the one directly under the heat conduct will boil faster and the second one already heating up pretty good before the heat excapes from the pipe...

is there any other good post for making boiling water rocket stoves for beer taht you  found?

I’ve been tinkering with a similar design to heat the Hot Liquor Tank — and then be able swap the HLT as a still boiler to harvest the ethanol after fermentation ..for refining biodiesel...
...and making hand sanitizer [I swear.]

Kinda following-up on Glenn’s reply...Depending on the construction of the pot you’re using for your HLT, the flue gasses could still be an issue with scaling ...like if your pot has a 3-ply bottom (2 layers of stainless steel with aluminum sandwiched between)

Even with water in the pot, the center will be intensely hot right above the riser, and that might damage a tri-ply sandwiched pot bottom... or warp and begin to corrode a single-layer stainless pot.

From AZOM materials fact sheet on 304 stainless (the grade used in almost all stainless cookware and most brewing equipment):

> “...grade 304 stainless steel possesses “good oxidation resistance in intermittent service to 870 °C and in continuous service to 925 °C.” However, they warn that “continuous use of 304 in the 425-860 °C range is not recommended if subsequent aqueous corrosion resistance is important.”

> 304H will become sensitized in the temperature range of 425-860 °C. Whilst this is not a problem for high-temperature applications, it will result in reduced aqueous corrosion resistance.

> ...In other words, you can expose grade 304 alloy steel to temperatures of up to 1,598 °F for short periods of time without ill effect, and for extended periods of time in temperatures of up to 1,697 °F. However, this can compromise the corrosion resistance of the metal, making it more susceptible to corrosion damage from exposure to moisture.”

That reduced aqueous corrosion resistance is problematic for our application, since we’re boiling water...And, since the flue gasses can reach 2000°F (or higher) in the localized center of the pot, that creates thermal stress issues as well. All of which would lead to accelerated rusting, wear, and then failure of the pot in the center of the bottom. This becomes even more of an issue considering the high carbon content of flue gas, which has a “carburizing” corrosion effect on stainless steels.

The design I’m toying with currently uses Peter’s batch box Double ShoeBox Rocket design, and harvests the heat indirectly (after it has gone through some cooling by dispersion — by warming a mass of basalt pebble and sand, in which the pot sits, acting as a double-boiler of sorts...or like a “heating mantle” used in laboratory settings to bring Pyrex distillation boilers up to temp.)

If you’re working from a J-Tube design, I would recommend using the full barrel over the riser, and then placing your pot on the top of the barrel. This will allow the barrel to bear the brunt of the heat dispersion, and will handle the carburizing effects of 2000°F flue gasses, instead of hitting your HLT directly with them. That barrel can be more cheaply and easily be replaced than a 304 stainless pot of that size...being more-or-less a sacrificial component of rocket mass heater design.

Personally, I’m working from the doubleshoebox rocket design, because A) it lays the riser sideways and affords me more working vertical height than the traditional rocket, and B) loading a batch-box frees me up to do other brewing duties, whereas a J-tube must be constantly tended with fuel while it burns.

Cheers

Cool idea for a brewery. I have a question, how do you move the wort from the kettle to the fermenter? When I make beer I use a kettle that has a valve on the bottom. After cooling the wort down I just open the valve and let it go in to the fermenter.

I've been wondering if a similar design could be used to boil maple sap to make maple syrup. Glad other people are on a similar mental track to me.

Plenty of people have built rocket-fired maple syrup evaporators - I have built two. Evaporators work differently from plain heating boilers; they need to be wide and flat because steam can only evaporate so fast from a square foot of surface area. Here is a description of one of my evaporators; the whole thread has a number of others, and there are plenty more threads if you search for "maple evaporator".