Plasticmetal
Member
Background:
Pasteurizing is a critical step in my brewing technique because I make a lot of stuff that is intended to finish off dry or semi-sweet, but at the same time is bottle-conditioned to have some carbonation. I started out using a stovetop method very similar to the one pinned in the cider forum, and upgraded to a turkey fryer to increase bottle count per iteration. However, for a batch of 25-30 bottle (I use 22 oz’ers) this could take upward of 2 or 3 hours and gets a bit long in the tooth by the end of it.
Last year I started looking at making my own bath pasteurizing setup that could knock out 35+ bottles in one iteration. Surprisingly, I haven’t found any resources or notes covering how to make one of these things to date, but hey, I might have missed something. After a some touch-and go runs and a few bottle bombs my current setup (covered below) has been in service now for over 9 months and can pasteurize an entire batch in less than 90 minutes, including setup and break-down time.
As a note for record: When dealing with full strength meads, anything still, or anything with cork I generally opt for chemical stabilization and do not recommend pasteurization.
Disclaimers:
Safety Hazard Statements:
Do this process outside – NO EXCEPTIONS
Theory of Operation:
The pasteurizer works by pumping water from the holding basin through a heating element, and discharging the heated water back into the basin at pressure. This enables:
On the topic of temperatures, I generally run between 140 and 150 F for 10 minutes, with the bottles in-bath as the water heats up. I’ve found anything above 150 to be unnecessary, and the consensus I’ve read dictates that 140 F is not survivable for yeast, with die-off starting at 120 F.
Components:
Holding Basin
Loose Ends:
Automations: A more savvy electrical type could probably rig up a PID control to keep temps stable. How much time that would actually save you, though, is debatable given that this setup would require monitoring regardless of automation level.
Bulk / Non bottled adaptations: I don’t see this being practical for non-packaged / bulk pasteurizing applications, but if you can figure out a way to do it that results in a palatable product and doesn’t ruin the equipment, let me know.
Operating Notes: I have operating notes for this system on-hand but putting them here would be a bit beyond the current scope of this post. Depending on the interest this thread generates, I might put any additional thoughts on this into a “Part II”.
Photos:
Pasteurizing is a critical step in my brewing technique because I make a lot of stuff that is intended to finish off dry or semi-sweet, but at the same time is bottle-conditioned to have some carbonation. I started out using a stovetop method very similar to the one pinned in the cider forum, and upgraded to a turkey fryer to increase bottle count per iteration. However, for a batch of 25-30 bottle (I use 22 oz’ers) this could take upward of 2 or 3 hours and gets a bit long in the tooth by the end of it.
Last year I started looking at making my own bath pasteurizing setup that could knock out 35+ bottles in one iteration. Surprisingly, I haven’t found any resources or notes covering how to make one of these things to date, but hey, I might have missed something. After a some touch-and go runs and a few bottle bombs my current setup (covered below) has been in service now for over 9 months and can pasteurize an entire batch in less than 90 minutes, including setup and break-down time.
As a note for record: When dealing with full strength meads, anything still, or anything with cork I generally opt for chemical stabilization and do not recommend pasteurization.
Disclaimers:
- I am not directing you to do anything mentioned here
- I am not guaranteeing any outcomes
- If you pursue this project or something similar, you do so at your own risk
Safety Hazard Statements:
Do this process outside – NO EXCEPTIONS
- The heating element I use produces carbon monoxide
- Always leave the basin lid on after initial fill
- Allow bottles to cool to below 100 F before handling / storing
- Store your brew in a containment area where they can burst with minimal consequence – there may have been something you missed
Theory of Operation:
The pasteurizer works by pumping water from the holding basin through a heating element, and discharging the heated water back into the basin at pressure. This enables:
- A controllable rise in water temperature
- Maintenance of a specific temperature or temperature range
- Adequate circulation to mix the water and prevent thermal stratification (easier to screw up than you might think)
On the topic of temperatures, I generally run between 140 and 150 F for 10 minutes, with the bottles in-bath as the water heats up. I’ve found anything above 150 to be unnecessary, and the consensus I’ve read dictates that 140 F is not survivable for yeast, with die-off starting at 120 F.
Components:
Holding Basin
- This is where you put the bottles and is the “Bath” in Bath Pasteurizer.
- Don’t overthink it.
- I use a 27-gallon Costco storage box – One of the ones with a yellow lid.
- If the outdoor temp is above 45 F, don’t sweat insulation. Note: I live in the Bay Area, CA, and we don’t have real seasons here. Still, this worked fine in the mid-50’s over last winter. For those in harsh environments, use your best judgement and if you find something that works, please reply to this thread.
- Critical for successful operation – If you cannot monitor temp, don’t even try this.
- Install probes at basin inlet & another at basin outlet, at staggered depths. Note: This is how you ensure adequate mixing is taking place – Temp should not be more than ~5 F off between probes.
- Temp alarm feature may or may not be useful (I’ve been fine without)
- I use a SMARTRO ST59
- There’s probably a better way to do this, but garden hoses allow for a lot of flexibility - I used ½” garden hose with ¾” hose fittings. Go to Home Depot and get 50 feet of cheap hose and like 7 hose repair kits if you go this route.
- All basin / pump / heater fittings are male, all hose fittings female
- I use brass hose bib shutoff valves as isolation / routing valves
- If using a pump with a ½” discharge, the basin inlet (pump discharge point inside of the basin) needs to be ½” to give adequate pressure for circulation. Note: Do not overlook this detail – Nozzle size directly impacts discharge pressure, which directly impacts circulation inside the basin.
- Protect your pump – Affix some sort of debris screen on the pump’s suction (basin outlet) tubing.
- I’ve found that fluid transfer pumps and fish tank pumps hit thermal cutoff and / or do not produce adequate discharge pressure for circulation. They are not advisable.
- After some trial and error, I ended up with a pressure booster diaphragm pump meant for water systems on boats and RV’s. It has a 5 GPM / 70 PSI rating and works great. (Google: FlowFluid 110 AC, on demand, self-priming booster pump)
- As general guidance for pumps, I would go with any positive-displacement pump rated more than 3-4 GPM and producing 50 PSI or greater. PSI = Circulation inside the basin and is the critical number to look at.
- I tried prototype iterations of this setup with a 2000-watt immersion water heater and concluded that the heating action was not sufficient. I didn’t want to buy a second one, nor did I want to see what happens to my residential electric system with several of these pulling at once. For the same reason I cannot endorse using one or several suis-vide heaters – the basin volume is too large for efficient and timely electric heating. Note: As always, anyone who has proved this hot take wrong please post your notes in this thread.
- I settled on a camping / RV tankless water heater running off propane – (Google: Forimo 4.21 GPM 16 L Outdoor Portable GasHot Water Heater)
- These heaters always have thermal cutoffs as an engineered safety feature – That cutoff needs to be 150 F + at a minimum, but the higher the better. Mine taps out at 167 F and works fine.
Loose Ends:
Automations: A more savvy electrical type could probably rig up a PID control to keep temps stable. How much time that would actually save you, though, is debatable given that this setup would require monitoring regardless of automation level.
Bulk / Non bottled adaptations: I don’t see this being practical for non-packaged / bulk pasteurizing applications, but if you can figure out a way to do it that results in a palatable product and doesn’t ruin the equipment, let me know.
Operating Notes: I have operating notes for this system on-hand but putting them here would be a bit beyond the current scope of this post. Depending on the interest this thread generates, I might put any additional thoughts on this into a “Part II”.
Photos:
