Fermentation Times

[stylus1274]

Hello -

I'm fairly new to brewing. Been doing it a short 2 years now.

I for the most part brew simple recipes. I generally leave my batch in the fermentor for 14 days and then move on to bottling.

I was reading the Anchor Steam clone recipes in the recent BYO Magazine. Each recipe listed the fermentation as one week and then bottle.

So I'm very curious about this as it seems short to me.

I've had brews take 10-12 days to finish. I wait the extra 2 to let it 'clean up' a bit.

I've also had a few finish in 7 but I still wait another 7 for the exact same reason.

Curious to what others think and your practices when brewing ales.


Thanks

 

[flars]

It is misinformation to state a time for a fermentation to be complete. There are just to many variables. Good thing is, the brewer, if they have some experience can question a recipe, as you did. Bad thing is, like misinformation in many kit recipes, the brewer may be just starting out and is mislead into brewing an inferior beer.

The typical time for the beers I brew is three weeks in the primary. At the end of three weeks the beer is clear, cake is compacted and ready to be bottled.

 

[HB_in_Subic]

I only bottle at 7 days if I am trying to get my pipeline populated. Otherwise, I usually let mine sit for 2-3 weeks and bottle when I have enough bottles available. The brews that I have let sit longer are usually the best ones.

 

[whiskeyjack]

2-4 weeks here then keg/bottle. Depends on when the beer gets finished and whether or not I'm kegging or bottling.

 

[stylus1274]

Thanks for the replies guys. I didn't think many would say they go 7 days. I was really surprised to see all the Anchor Steam recipe clones listed as such.

It's the first time in that magazine I've seen such short ferment times.

Even if the majority of you said you did that, I'm unlikely to reduce my time.

 

[MEPNew2Brew]

I have been trying to speed up my brewing process to fill the my relatively new keezer (5 kegs). So far, I think it is far easier to just let it sit three weeks, rather than trying to figure out when it is "done." For example, I have a Zombie Dust clone - terminal gravity reached in a week. But, the yeast are not done their work - need to clean up diacetyl.

 

[stylus1274]

For example, I have a Zombie Dust clone - terminal gravity reached in a week. But, the yeast are not done their work - need to clean up diacetyl.

That is what I was thinking MEP. There is still work to be done even though terminal gravity has been reached.

 

[hannibalmdq]

I know this is neither and a common or uncommon philosophy, but it's what I believe.

If you're pitching a proper amount of healthy yeast and controlling your temps, (pitch low, hold through the bulk of the attenuation, then raise temps to finish and clean up) you can be done fermentation in 2 to 3 days and cleaned up somewhere between day 6 and 10 for low to moderate OGs.

Different yeast, different timelines. Stressed yeast, different timeline. Huge OG, different timelines. Different temperature profile, different timeline.

That's not to say that some yeast aren't a stubborn floc and that flavors don't continue to change over time, but the fermentation and yeast derived portion of the flavor contribution is largely over a lot sooner than generally accepted.

 

[stylus1274]

If you're pitching a proper amount of healthy yeast and controlling your temps, (pitch low, hold through the bulk of the attenuation, then raise temps to finish and clean up) you can be done fermentation in 2 to 3 days and cleaned up somewhere between day 6 and 10 for low to moderate OGs.
.

This is interesting because I tested a new dry yeast in a recent brew. It went from 1.056 down to 1.008 in 3 days. It is Mangrove Jack's Belgian. So I've been letting it clean up for the last 5 and will go all the way to 14 days.

Before that I had a 1056 do 'its' job in less than 5 days.

My big worry and MEP mentioned it is diacetyl. I like to bring up the temp and do the rest for a few days. Last thing I want is a mouth full of butter

 

[hannibalmdq]

This is interesting because I tested a new dry yeast in a recent brew. It went from 1.056 down to 1.008 in 3 days. It is Mangrove Jack's Belgian. So I've been letting it clean up for the last 5 and will go all the way to 14 days.

Before that I had a 1056 do 'its' job in less than 5 days.

My big worry and MEP mentioned it is diacetyl. I like to bring up the temp and do the rest for a few days. Last thing I want is a mouth full of butter

The pathways for diacetyl production and cleanup are fairly well understood. Production and cleanup is roughly a curve and it's affected by temperature quiet a bit.

The best way to control diacetyl is to go through the initial portions of fermentation at a lower temperature than the last portion. Yeast start cleaning up diacetyl towards the tail end of attenuation and continue for a few days. By keeping the temperature down during the bulk of attenuation you supress the production of diacetyl and by raising it at the tail end you encourage it's uptake. (Source: Yeast and other books on fermentation).

My personal opinion is that temps should start to be raised by the 70 to 90 % attenuation mark, which often happens between day 2 and 3 for the yeast strains that I work with (chico, notty, wlp028) at the gravities (1.040 to 1.060) and volumes (3 gallons) I brew at. If I waited a week to raise temps, the yeast are basically done the clean up portion of their cycle anyway. Raising the temperature at that point would have reduced effectiveness since the yeast are all "asleep" at that point anyway.

The beer will continue to condition (all I mean with that is it will change with time) for as long as you let it set but yeast don't really continuing actively processing stuff for weeks and weeks and weeks.

Pro-brewers with yeast byproducts they want to clean up will sometimes pitch actively fermenting wort so those active yeast will go through their clean-up process on the beer they are trying to correct. They aren't doing that to eke out more points. They are doing it to introduce yeast in the proper phase to the beer that needs "cleaned". Raising the temp of the already inactive yeast wouldn't likely have the effect they are looking for.

 

[stylus1274]

Awesome information Hannibal. I will look to start that a bit earlier then based on this info.

Quick question. About how much do you raise temps to do this generally speaking? A couple degrees? More?

 

[hannibalmdq]

Awesome information Hannibal. I will look to start that a bit earlier then based on this info.

Quick question. About how much do you raise temps to do this generally speaking? A couple degrees? More?

I'm still figuring out how I like the yeast strains I'm working with. Normally I'm fermenting at the low end of the yeasts range. Once I decide to ramp I'll normally raise it by a 2 degrees in the morning and another 2 degrees in the evening until I'm up at the upper range then hold for a few days. After that, I just let it sit at ambient, whatever that may be (normally between 70 and 76).

Note, yeast tend to stay in suspension longer at high temps, so depending on the strain, you might notice longer floc times or consider cold crashing before you package.

Personally, I'm a little skeptical that the upper bound of temperature really matters all that much after attenuation. Out of curiosity, I took a chico brown ale ferment from 64 and just pulled it out of the chamber after 3 days and let it come up to ambient (75ish) as quickly as it wanted to. Quick and clean fermentation.

Again, your mileage my vary and a lot of this depends on how you like your ferments to taste. I'm just gathering data and experience at this point and only working with a few strains to get very familiar with them. People working on a nice estery English ale would probably disagree with plenty of this.

 

[stylus1274]

Funny you mention the ambient temperature thing.

I have a strain that has suggested ferment temps between 79 - 90. Neither of those temps I can keep in my house. I live in Florida so I'm use to always cooling down my fermenter not heating it up

I am leaving it at 76 which is about the warmest I can get it. Hoping it comes out OK and don't have much of an issue with diacetyl.

 

[hannibalmdq]

Funny you mention the ambient temperature thing.

I have a strain that has suggested ferment temps between 79 - 90. Neither of those temps I can keep in my house. I live in Florida so I'm use to always cooling down my fermenter not heating it up

I am leaving it at 76 which is about the warmest I can get it. Hoping it comes out OK and don't have much of an issue with diacetyl.

You'll probably be fine regardless of what you do at this point. There's just a lot of advice that floats around that seem to run counter to what is known about how yeast behaves, especially regarding the length of time where yeast is active after fermentation.

Regardless, you can make great beer a large number of ways and yeast are pretty tolerant organism all things considered.

The one thing I'm fairly sure is bad advice is telling someone they can "save" a hot ferment by lowering the temperature at day 3/4. All you'd be doing that point is reducing the yeast activity during the period its cleaning stuff up. This is after allowing it to be really active during the period it produces most of it's off flavors.

Assuming that attenuation is mostly/complete at that point, I feel that better advice might be to make sure temps don't naturally fall off. At least then you'd be encouraging it to clean up as much as it can it. This would certainly be the case for compounds like diacetyl.

 

[stylus1274]

What do you mean by make sure temps don't naturally fall off?

 

[hannibalmdq]

What do you mean by make sure temps don't naturally fall off?

The reproductive phase of yeast is exothermic. So if your carboy is sitting in a 70 degree room and you pitch your yeast, you might come back a 36 hours later to find that the room is still at 70 but your carboy is now at 76. The yeast are mostly done reproducing at that point and decided to come back and check at 72 hours, and the carboy has cooled back off 72. It will continue to fall back to 70 degrees.

You haven't done anything to change the temperature of your wort, but the yeast sure did.

What a ferementation curve like this means is that during the first phase of ferementation, the yeast made themselves hotter, and threw off more of the compounds we would consider off-flavors than if the temperature had been artificially held at 70 during that phase of activity.

As attenuation wraps up, the yeast start processing some of those compounds into other less offensive by products and start to uptake other compounds as they prepare to go dormant. However, since the wort has naturally cooled off, they do so in an environment that is cooler than what they were producing those off-flavors in. They end up leaving more of those unwanted flavors in the finish beer.

That's what I mean by naturally falling off.

Now, lets take a new brewer, who brewed up 1.050 of some kit nut brown ale. They put it in the their basement because it a few degrees cooler than their second floor closet. They pitched their yeast, and check on it 2/3 days later and find that it's warmer more than it ought to be so they run to HBT and someone tells them to throw it in an ice bath and cool it off 10 degrees.

I'd posit that better advice for them would be to move it up to their second floor closet and keep the beer at that warmer temp as ferementation wraps up and the yeast start to clean up and uptake some of those off flavors. I think they may end up with a cleaner beer going that route than slamming the yeast with a 10 degree drop just as they are trying to tidy up before taking a nap.

Anyway, it's just something I've mulled over when looking at people responding to the Beginners Brewing section.

It all ends up as beer anyway.

 

[kombat]

Fermentation produces heat, so the temperature of the beer will be warmer than the surrounding air during peak fermentation. As fermentation winds down, less heat is produced, so the temperature of the beer drops back towards the ambient temperature, which further encourages the yeast to fall out and go to sleep. He means to artificially hold the temperature at (or slightly above) where it was during peak fermentation, when the yeast were producing the heat. This will encourage the yeast to keep working and clean up after themselves, even as they'd prefer to be winding down since all the fermentable sugar is gone.

 

[stylus1274]

Thanks for the thorough explanation Hannibal. That makes a lot of sense.

I'm aware the fermentation produces heat. I generally control my temps throughout. I very rarely if ever let it sit 'naturally'.

These last few batches have proven a bit harder because of the cooler weather.

 

[broadbill]

The reproductive phase of yeast is exothermic. So if your carboy is sitting in a 70 degree room and you pitch your yeast, you might come back a 36 hours later to find that the room is still at 70 but your carboy is now at 76. The yeast are mostly done reproducing at that point and decided to come back and check at 72 hours, and the carboy has cooled back off 72. It will continue to fall back to 70 degrees.

You haven't done anything to change the temperature of your wort, but the yeast sure did.

What a ferementation curve like this means is that during the first phase of ferementation, the yeast made themselves hotter, and threw off more of the compounds we would consider off-flavors than if the temperature had been artificially held at 70 during that phase of activity.

As attenuation wraps up, the yeast start processing some of those compounds into other less offensive by products and start to uptake other compounds as they prepare to go dormant. However, since the wort has naturally cooled off, they do so in an environment that is cooler than what they were producing those off-flavors in. They end up leaving more of those unwanted flavors in the finish beer.

That's what I mean by naturally falling off.

Now, lets take a new brewer, who brewed up 1.050 of some kit nut brown ale. They put it in the their basement because it a few degrees cooler than their second floor closet. They pitched their yeast, and check on it 2/3 days later and find that it's warmer more than it ought to be so they run to HBT and someone tells them to throw it in an ice bath and cool it off 10 degrees.

I'd posit that better advice for them would be to move it up to their second floor closet and keep the beer at that warmer temp as ferementation wraps up and the yeast start to clean up and uptake some of those off flavors. I think they may end up with a cleaner beer going that route than slamming the yeast with a 10 degree drop just as they are trying to tidy up before taking a nap.

Anyway, it's just something I've mulled over when looking at people responding to the Beginners Brewing section.

It all ends up as beer anyway.

The core mistake made by the brewer in your example is not that he abruptly changed the temperature at the tail-end of the fermentation, is that is was too hot to start with. As you mentioned, a 70F ambient will mean a 76-80F fermentation temp which is well out of the range of the yeast optimum of mid-60s.

It should be pointed out that starting the fermentation at the correct temperature (and maintaining it) will obviate the need for extreme back-end corrections.

The best advice would be to avoid extreme temperature fluctuations in general.

 

[hannibalmdq]

Thanks for the thorough explanation Hannibal. That makes a lot of sense.

I'm aware the fermentation produces heat. I generally control my temps throughout. I very rarely if ever let it sit 'naturally'.

These last few batches have proven a bit harder because of the cooler weather.

Yeah, I think most people know about the heat of ferementation. My exposition wasn't really directed at you, it was just a general brain dump regarding some of the stuff I see written about the tail end of what yeast does.

I think post attenuation yeast-cleanup and general conditioning/aging of beer aren't widely seen as two separate processes with different inputs.

 

[hannibalmdq]

The core mistake made by the brewer in your example is not that he abruptly changed the temperature at the tail-end of the fermentation, is that is was too hot to start with. As you mentioned, a 70F ambient will mean a 76-80F fermentation temp which is well out of the range of the yeast optimum of mid-60s.

It should be pointed out that starting the fermentation at the correct temperature (and maintaining it) will obviate the need for extreme back-end corrections.

The best advice would be to avoid extreme temperature fluctuations in general.

I totally agree with what you've said here. The optimal case is the brewer plans his next batch a little better.

I'm just thinking of the specific advice that brewer ask for which is, "help me take what I've already done and try to make it as good as it can be." Given what's already happened, it may well be the case that the cooled off beer doesn't taste significantly better than the beer held at a high temperature. That being said, I still think that would be their best shot. I think you can tell them that what to do with the batch they have is different than what they should do with their next one.

Not starting at the right temp was their mistake. Telling them they should lower it as ferementation is falling off would be "our/HBT's" mistake.

 

[stylus1274]

I agree with Hannibal. I think your starting ferment temp goes without saying. I mean I'm not pitching my yeast at 78 when I want to ferment at 60.

I see a lot of recipes and such that say pitch at 80. I don't see the point in that. If I want to ferment at 66, then I pitch as close to that as possible and maintain that temp.