Anybody Pasteurizing Their Beers?

[Broothru]

I came across an article in Craft Beer & Brewing talking about Pasteurization in commercial and home brewing. This lead to a necro thread here on HBT, with the end result being a lot of math, some science, and a lot of opinions. The main take-away from going down this rabbit hole was that heating capped bottles of home brew in 60C/140F water for 15~30 minutes would actually result in Pasteurized (don't conflate with sterilized) home brew. Heating and maintaining a bottled beer for each minute @ 60C/140F = 1 PU (Pasteurization Unit). Commercial standards for breweries range from 5-100 PUs, with 20~30 being average values, and with 50 PUs recommended for NA beers. There's a formula for determining time/temperature equivalents for Pasteurization Units using different protocols; i.e., flash, tunnel, etc., methodologies, but 25 PUs appears to be the sweet spot for home brewing beer, sweet ciders and meads.

Is anyone currently using Pasteurization in their home brewing? In some correspondence I had recently with Brad Smith (BeerSmith) he minimized the risks of pathogens in beer due to the presence of alcohol and the antibiotic properties of hops, assuming otherwise normal handling and sanitation by the brewer (you and me). This becomes problematic in the case of LA/NA beers due to the absence of alcohol. The trend is toward lower alcohol, and there are increasing availability of ingredients and recipes for brewing Non-alcoholic home brew. I've been interested in following this trend in my brewing, but have resisted the temptation so far due to the potential health risks. This hot water bath approach seems easy and doable (sous vide precision temperature controlled bath). The science is pretty straight forward, as long as bottles don't start exploding!

So getting back to the original question, is anybody doing this? What have been your experiences, good and bad? Sous vide method would be precise and safe, as long as the beer wasn't bottle conditioned and carbonated, and the fermentation had been allowed to fully complete to terminal gravity. Assuming good oxygen mitigation from mash to packaging, the brief exposure to high temperature shouldn't result in premature staling. I want to try this, but first I want to hear about any missteps as well as successes.

 

[Skeeter686]

Sous vide method would be precise and safe, as long as the beer wasn't bottle conditioned and carbonated, and the fermentation had been allowed to fully complete to terminal gravity.

I've only tried it once as part of a (possibly weird) experiment to stabilize the beer (i.e., kill the yeast... RIP, my beer-making friends!) so that I could backsweeten the beer a bit without being forced to use artificial sweeteners.

But I'm curious about the assertion that carbonated beer couldn't be Pasteurized. Is the concern that the heat would cause the carbonation to cause bottle bombs?

I've heard about using Pasteurization on bottled sparkling mead to stop the fermentation and leave some residual sugar behind. I've never tried it, and it does seem like you'd need a lot of precision and control to do it safely and effectively, but is it really unadvisable / dangerous?

 

[mac_1103]

Cider makers have been know to heat pasteurize after bottle conditioning. Check out this thread for instance. Maybe I'll even tag @Chalkyt to see if he might have more advice for us beer folk.

 

[mashdar]

IMO the biggest anti-microbial deficiency of low ABV beer is that the yeast may not drop the pH low enough. In my experience, this is mostly an issue below 1%, but depends on yeast, buffering capacity, etc. I do a lot of ~3% brewing that ends at a similar pH to its 5-6% cousins.

Acidification to ~4.4 is easy enough, and should probably happen immediately after chilling if you're looking to maximize safety on a <1% ABV beer.

edit: Even the fermentation time of a few days at elevated pH supposedly* puts beer into botulism-danger-zone, regardless of ABV and hops. Hops may (very likely) have anti-botulism properties, but it has not been rigorously demonstrated in beer AFAIK.
*According to US FDA

 

[Climb]

I have pasteurized bottle conditioned cider in capped standard 12 ounce bottles. I used two water baths on the stove top. The first pot at about 125F and the second one at 160 F. I’d leave the bottles in the first pot for about 10 minutes and then move them to the second pot for another 10 minutes. I quickly learned to keep a lid on each pot as out of a 5 gallon batch I would always have a bottle or two explode. I have stoped doing this as it was labor intensive, time consuming and dangerous. I now keg my ciders and just keep them cold when I want fermentation to stop to get the right level of sweetness. Maybe you could do the same thing with your NA beers.

 

[AzOr]

While I can't speak to the LA/NA beers being at a higher risk of infection, I have been pasteurizing ciders and mead for years. It's a giant pita, but here's a few pointers for those who may be interested.
-I would purchase/borrow/steal the largest vessel possible. I have my mom's old enamel tamale pot that can fit about 14 12 oz'ers.
- I use my old propane single burner, not sous vide (although that's a good option). If using a burner/pot, purchase a false bottom so your beers aren't sitting on the bottom.
-You may be tempted to save time by bottling 22oz bombers, but in my experience, those have been the only bottles to explode*. If you're looking for a drama free time, use 12 oz bottles.
-Use a "dummy" bottle to check temps. I fill a bottle with water (match the temp of the beer) and place a rubber bung on top. Those kind with a hole for an airlock. This way I can easily slip my thermal pen in and check the temp. Be careful not to knock the bottles around.
-Once the temp hits about 145-150f, I turn off burner and let sit for about 10 minutes while I clean/prep, do other stuff.
-If at all possible, do this outside with safety gear. I use safety glasses and those elbow length bbq heat gloves. I place a few towels on an outside table to gently set down and cool after pasteurizing.

*I have had a half dozen or so "explode" on me. It's always been the 22 oz bomber bottles. When I say explode, typically they make a loud noise and just sever on the neck somewhere. They have never sent glass shooting anywhere though. The noise is enough to bring your attention back to the game.
My breakage ration is probably 1 for every 200 bottles, roughly. You occasionally will have the crowns pop off.

One last thing, the stated pasteurization units seems a little high but that could be the diff between beer and cider.

 

[Broothru]

While I can't speak to the LA/NA beers being at a higher risk of infection, I have been pasteurizing ciders and mead for years. It's a giant pita, but here's a few pointers for those who may be interested.
-I would purchase/borrow/steal the largest vessel possible. I have my mom's old enamel tamale pot that can fit about 14 12 oz'ers.
- I use my old propane single burner, not sous vide (although that's a good option). If using a burner/pot, purchase a false bottom so your beers aren't sitting on the bottom.
-You may be tempted to save time by bottling 22oz bombers, but in my experience, those have been the only bottles to explode*. If you're looking for a drama free time, use 12 oz bottles.
-Use a "dummy" bottle to check temps. I fill a bottle with water (match the temp of the beer) and place a rubber bung on top. Those kind with a hole for an airlock. This way I can easily slip my thermal pen in and check the temp. Be careful not to knock the bottles around.
-Once the temp hits about 145-150f, I turn off burner and let sit for about 10 minutes while I clean/prep, do other stuff.
-If at all possible, do this outside with safety gear. I use safety glasses and those elbow length bbq heat gloves. I place a few towels on an outside table to gently set down and cool after pasteurizing.

*I have had a half dozen or so "explode" on me. It's always been the 22 oz bomber bottles. When I say explode, typically they make a loud noise and just sever on the neck somewhere. They have never sent glass shooting anywhere though. The noise is enough to bring your attention back to the game.
My breakage ration is probably 1 for every 200 bottles, roughly. You occasionally will have the crowns pop off.

One last thing, the stated pasteurization units seems a little high but that could be the diff between beer and cider.

My thought also was 50 PUs seemed a bit high. If 15 PUs is considered safe for killing off bad microbes, then 50 PU seems a bit much. Since 'time' appears to be exponential with 'temperature' (e.g., 30 minutes @ 140F vs. 75 seconds @ 170F) the difference may be more dependent on the method of heat application.

For instance, tunnel Pasteurization may rely on a more uniform and quicker transference of higher peak heating than is capable in a water bath, where the transference of heat through the bottle glass to achieve uniform temperature to denature microbes within the entire volume of beer takes longer. Maybe the metaphor of seared meat over intense heat as opposed to slow cooked meat for a longer period of time to reach a food safe internal temperature is apropos. It could be that :30 mins @ 140F = 50 PUs is more of a safety margin, at the lower risk of bottle bombs and possible degradation of beer quality inside the bottle.

The risk of exceeding bottle integrity would likely be a lot higher at 170F than 140F. I really have no clue as to the temperature and pressure combination where dissolved CO2 to evolved gaseous state occurs, but it would certainly be lower at 140F than 170F. Consider how the volume of water expands and pressure spikes in the same 30F range between 182F and 212F combined with the associated phase change between liquid H20 and gaseous steam. If the vapor pressure of evolving CO2 is spiking between 140F-170F, so is the risk of bursting bottles.

Also as you point out, the risk doesn't end with removal of the bottles from a warm water bath, though the 'drama' associated with such a failure is usually on a lesser order of magnitude. Thermal shock is most likely the culprit there, and again, having a lesser differential between water bath temperature and the cooling ambient temperature can be an important factor. The obvious downside is the longer exposure to higher temperature and the adverse affect it might have on beer quality, although anecdotally the heat and denaturing of "bad bugs" would help the microbial stability of the beer. So, there's that!

 

[BrewZer]

I came across an article in Craft Beer & Brewing talking about Pasteurization in commercial and home brewing. This lead to a necro thread here on HBT, with the end result being a lot of math, some science, and a lot of opinions. The main take-away from going down this rabbit hole was that heating capped bottles of home brew in 60C/140F water for 15~30 minutes would actually result in Pasteurized (don't conflate with sterilized) home brew. Heating and maintaining a bottled beer for each minute @ 60C/140F = 1 PU (Pasteurization Unit). Commercial standards for breweries range from 5-100 PUs, with 20~30 being average values, and with 50 PUs recommended for NA beers. There's a formula for determining time/temperature equivalents for Pasteurization Units using different protocols; i.e., flash, tunnel, etc., methodologies, but 25 PUs appears to be the sweet spot for home brewing beer, sweet ciders and meads.

Is anyone currently using Pasteurization in their home brewing? In some correspondence I had recently with Brad Smith (BeerSmith) he minimized the risks of pathogens in beer due to the presence of alcohol and the antibiotic properties of hops, assuming otherwise normal handling and sanitation by the brewer (you and me). This becomes problematic in the case of LA/NA beers due to the absence of alcohol. The trend is toward lower alcohol, and there are increasing availability of ingredients and recipes for brewing Non-alcoholic home brew. I've been interested in following this trend in my brewing, but have resisted the temptation so far due to the potential health risks. This hot water bath approach seems easy and doable (sous vide precision temperature controlled bath). The science is pretty straight forward, as long as bottles don't start exploding!

So getting back to the original question, is anybody doing this? What have been your experiences, good and bad? Sous vide method would be precise and safe, as long as the beer wasn't bottle conditioned and carbonated, and the fermentation had been allowed to fully complete to terminal gravity. Assuming good oxygen mitigation from mash to packaging, the brief exposure to high temperature shouldn't result in premature staling. I want to try this, but first I want to hear about any missteps as well as successes.

Not me. I LIKE my beers to age in the bottle.

 

[marc1]

I came across an article in Craft Beer & Brewing talking about Pasteurization in commercial and home brewing. This lead to a necro thread here on HBT, with the end result being a lot of math, some science, and a lot of opinions. The main take-away from going down this rabbit hole was that heating capped bottles of home brew in 60C/140F water for 15~30 minutes would actually result in Pasteurized (don't conflate with sterilized) home brew. Heating and maintaining a bottled beer for each minute @ 60C/140F = 1 PU (Pasteurization Unit). Commercial standards for breweries range from 5-100 PUs, with 20~30 being average values, and with 50 PUs recommended for NA beers. There's a formula for determining time/temperature equivalents for Pasteurization Units using different protocols; i.e., flash, tunnel, etc., methodologies, but 25 PUs appears to be the sweet spot for home brewing beer, sweet ciders and meads.

Is anyone currently using Pasteurization in their home brewing? In some correspondence I had recently with Brad Smith (BeerSmith) he minimized the risks of pathogens in beer due to the presence of alcohol and the antibiotic properties of hops, assuming otherwise normal handling and sanitation by the brewer (you and me). This becomes problematic in the case of LA/NA beers due to the absence of alcohol. The trend is toward lower alcohol, and there are increasing availability of ingredients and recipes for brewing Non-alcoholic home brew. I've been interested in following this trend in my brewing, but have resisted the temptation so far due to the potential health risks. This hot water bath approach seems easy and doable (sous vide precision temperature controlled bath). The science is pretty straight forward, as long as bottles don't start exploding!

So getting back to the original question, is anybody doing this? What have been your experiences, good and bad? Sous vide method would be precise and safe, as long as the beer wasn't bottle conditioned and carbonated, and the fermentation had been allowed to fully complete to terminal gravity. Assuming good oxygen mitigation from mash to packaging, the brief exposure to high temperature shouldn't result in premature staling. I want to try this, but first I want to hear about any missteps as well as successes.

Where's the discussion on how to determine appropriate PUs? And calculate appropriate treatment times and temps?
This is interesting because I remember reading about the canned wort that is being sold, and how it was made safe through Pasteurization at a certain number of PUs. (IIRC). I was interested that sterilization was not required, but couldn't find more info about it at the time.
I still plan to pressure can my starter wort, but this can satisfy some curiosity.

 

[Skeeter686]

Where's the discussion on how to determine appropriate PUs? And calculate appropriate treatment times and temps?

I did some reading on this, but I'm certainly not an expert. However, from what I've read, this is the impression that I get:

• There is a formula that you can use to determine "time at temperature" equivalents for the same number of PUs
• There are constants in this formula, which are specific to a food item (or maybe actually the types of micro-organisms relevant to a specific food), so you can't use the same equivalents for different types of food / beverage
• These constants are determined experimentally
• Beer is well-studied, and there's a commonly cited formula for beer: PU=t⋅1.393^(T−60)
• I get the impression that the formula for beer may also be used for ciders and meads

I never did find a really good article that walks through all of this in detail. Or maybe I just got tired of trying to find one.

Here's a thread on the topic of PUs:
https://www.homebrewtalk.com/threads/pasteurization-time-and-temperature-for-cider.581913/

 

[Broothru]

I did some reading on this, but I'm certainly not an expert. However, from what I've read, this is the impression that I get:

• There is a formula that you can use to determine "time at temperature" equivalents for the same number of PUs
• There are constants in this formula, which are specific to a food item (or maybe actually the types of micro-organisms relevant to a specific food), so you can't use the same equivalents for different types of food / beverage
• These constants are determined experimentally
• Beer is well-studied, and there's a commonly cited formula for beer: PU=t⋅1.393^(T−60)
• I get the impression that the formula for beer may also be used for ciders and meads

I never did find a really good article that walks through all of this in detail. Or maybe I just got tired of trying to find one.

Here's a thread on the topic of PUs:
https://www.homebrewtalk.com/threads/pasteurization-time-and-temperature-for-cider.581913/

That was the necro thread.

 

[sibelman]

the brief exposure to high temperature shouldn't result in premature staling.

I realize this thread is, correctly, focused on the serious technical issues, like achieving the result without injury. I'm wondering about the effects on flavor. If lowering the pH is good enough and doesn't noticeably affect flavor, maybe that's a straighter path to safety with low alcohol beverages?

 

[G_robertus]

Food microbiologist here. Beer is an incredibly safe beverage in terms of microorganisms because >2.5% ABV takes care of most harmful things. Same for pH <4.3 from the top of my head. Beer typically gets to these levels rather quickly. Hops also inhibit some (but certainly not all) bacteria.

Regarding NA/LA beer, pH should be your first concern. Getting it down to safe levels inhibits most harmful bacteria quickly. Pasteurisation will help to stop potential refermentation as well as knock out the last few harmful organisms if they are still there. One thing to note is that pasteurisation will not kill botulism spores nor will it destroy the toxin. Spores only die at pressure cooker temps (>121°C) and the toxin degrades above 85°C. Fortunately this stuff doesn't grow fast and it's inhibited by low pH and oxygen. It's unlikely to produce toxins before brewing and the toxins get destroyed in the boil anyway. However, this is why you need to get your pH down as soon as you stop boiling. Same goes for canned wort, although I would still pressure cook it myself if I had the ability (or boil before using).

I don't know much about PUs (I look up a chart if needed), so I can't help there. I've tried pasteurising beer before and it was not that hard to do, but I didn't gain anything from it. I'm not sure it did the flavour any good and despite being very careful I was constantly scared of exploding stuff. I did heat and cool from and to RT in the bath though and I think that should mitigate some of the risk.
I want to dabble into LA beer again soon, but I will go the extremely low sugar content route. There will be very little to consume for any uninvited yeast (hence no refermentation) and I plan to knock down the pH immediately after a short boil. I'll probably keg it though, since I don't want extra alcohol produced by bottle conditioning.

Tl;Dr boil and pH <4.3
N.b. I don't know everything, these are just the things I've looked into and am comfortable with doing myself.

 

[sibelman]

pasteurisation will not kill botulism spores nor will it destroy the toxin. Spores only die at pressure cooker temps (>121°C) and the toxin degrades above 85°C

I had the impression that botulism was the main health concern with LA/NA beer. So I wonder: are other harmful-to-humans bacteria potentially present in low-alcohol beer, that would be addressed by pasteurization? Or is pasteurizing beer done only to mitigate staling by microbes that are otherwise harmless to humans?

Here's a link to a piece about (regular, not LA/NA) beer pasteurization. Doubtless, there's greater wisdom out there.

 

[G_robertus]

I had the impression that botulism was the main health concern with LA/NA beer. So I wonder: are other harmful-to-humans bacteria potentially present in low-alcohol beer, that would be addressed by pasteurization? Or is pasteurizing beer done only to mitigate staling by microbes that are otherwise harmless to humans?

Here's a link to a piece about (regular, not LA/NA) beer pasteurization. Doubtless, there's greater wisdom out there.

It's one of the concerns. The problem with botulism is that the bacteria and its relatives are ubiquitous and can be found nearly anywhere. The good part is that you can deal with it relatively easily. Other potential hazards include, but are certainly not limited to, Salmonella, pathogenic E. coli and perhaps Listeria. Bacillus is also quite widespread and can form spores and toxins. These are frequently found in food production facilities and can be hard to get rid off. Most still suffer from low pH though.

I'm not completely convinced about your link as they advice against drinking unpasteurised beer altogether, though I would dare to say most beer I drink is unpasteurised. Yes there are always risks, but to outright say it is unsafe is a bit much. Same for the notion that pasteurisation kills everything bad (which it doesn't). There are some good pointers though.

Edit: After writing this post I found this article as well where apparently they found at least one Salmonella strain and one pathogenic E. coli strain can apparently survive at relatively low pH. That would merit pasteurisation in NA/LA beer, though the effect of temperature seems to indicate that over time they will die off albeit after a very long time. They don't specify viability, pathogenicity or virulence of the surviving bacteria which I would think would be very interesting to look at as well. It does mean that you should be extra careful when making NA/LA beer. At the same time, if you do it at home it likely means that it would've come from something in or around you or your house, so that would probably be a concern anyway. Wash your hands before/during brewing and especially packaging.

Edit2: wash your hands in general, not just when brewing.

 

[Ninoid]

Isn't it easier to use a chemical preservative?
Or, if forced carbonation is used, pasteurize the beer and then transfer it to a keg and carbonate it?
Anyway, I think that in home brewing, pasteurization is unnecessary. Commercial production can certainly benefit from pasteurization or chemical preservation.

 

[Skeeter686]

Isn't it easier to use a chemical preservative?

It's certainly easier. I believe one reason to avoid chemicals is that some people are sensitive to sulfites.

 

[Dan_Scott]

I bottle pasteurize carbonated cider regularly, and have some a couple bottles of beer here and there as well. I use my brew kettle and a sous vide (and now that I have a false bottom, some stovetop assist) and the information in this old thread (https://www.homebrewtalk.com/threads/heat-pasteurizing-and-carbonation-more-stuff.684883/). I target 12 minutes at 149 to get around 40 PU's; never had any explosions, never had any carbonated and backsweetened ciders restart on me. So I guess it works!

Honestly, it's not very hard or complicated once you have your process down, and having a sous vide makes it easy easier. One thing I always do is fill an empty bottle with water at room temperature and sit a leave in thermometer in it, and if I do get fluctuations in water temperature (happened a fair bit the first few batches, now I now to start with slightly hotter water) then I use that to just make sure I get the liquid temperature up to 147.

 

[Hoppy2bmerry]

Cider makers have been know to heat pasteurize after bottle conditioning. Check out this thread for instance. Maybe I'll even tag @Chalkyt to see if he might have more advice for us beer folk.

I have done this, though I went with a lower temp (still high enough to cook the yeast) for a longer duration. I’m also interested in making NA LA homebrew using a proper yeast for the job hops should matter in the preservation, but in regular beer there is of course alcohol. NA beer the PH may be kept on the acid side. Later I’ll look for an article I recently read- I think it was Omega that went into how the pros do it (Also why it’s expensive).