fermentation seems to have stopped after 2 days

i brewed a porter on sunday at about 4pm. i believe it began fermenting about 16 hours later, give or take an hour. the temp was about 72, there was a nice layer of foam, bubbles, and a lot of movement going on inside. the problem is, early tuesday morning, i discovered the nice foam and movement in the fermentor had pretty much ceased, as well as the bubbles. i also discovered the temp had dropped from about 72 to 65. im just now trying to bring the temp back up with a space heater. but i cannot keep it on all the time cause i work a lot, so the temp may drop a little bit. right now its about 71, but still no changes have occured. my question, if your yeast falls asleep cause the temp dropped and you warm it back up, gennerally how long should it take to get active again? also, could something else have happened here?
thanx
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I've had a few beers with no activity after two days. What kind of yeast did you use?

And the important question - did you take gravity readings?

I wouldn't raise the temp, a cooler temp in the 60 is actually preferable to prevent off flavors from stressing out the yeasts...

Even though the physical signs of fermentation appear to have ceased it more than likely didn't...The yeasts are still chewing the sugar and peeing alcohol...it's just not kicking up a lot of gunk and CO2 to trip the airlock...I have a strong belgiian doing the same thing.

Just leave it alone for a week or 10 days minimum (I leave mine for a month unless I'm dry hopping then I rack to secondary)

After 10 days take a hydro reading and another on 12 days. If it's the same you can decide to rack to secondary...or you can forget about it for a few more weeks then bottle...

But don't let your eyes deceive you...you may not detect the presence of fermentation..but the yeasties know what they're doing...

And forget raising the temperature!!! LEAVE IT ALONE!!!!

Everything's fine...

Oh read this as well. http://blogs.homebrewtalk.com/Revvy/Think_evaluation_before_action/

well, ashamed to say it im fermenting a little over 2 gallons in a mr. beer keg. i dont have access to a hydrometer. i used 2 cans mr beer malt extract, 1/2 cup of browm sugar, 1/2 oz. goldings pellet hops, and the mr. beer yeast. also, i just tossed the hops in with no bag, and dont plan on filtering. according to the mr beer yeast, it said proper ferm temps were between 68 to 76. why should i not try and get it a little warmer? do u have any expierience with mr beer or this problem?

beers in general should be fermented at cooler temperatures. For ales its usually somewhere in the 60's and for lagers its 40s. At higher temperatures you can get off flavors in your beer because of a different type of alcohol being produced at higher temp.

In general you should wait at least 3 weeks before you bottle. So try to keep it at 68 or lower unless this is some kind of Belgian recipe that needs warmer temps? I highly doubt that because I dont think Mr beer yeast is even sophisticated to replicate Belgian "taste" that a liquid yeast can. I am btw brewing next batch with a liquid Belgian (my 3rd batch with liquid). Only time can tell how much better it will be then my 2nd batch (AHS Blue Moon clone).

dogfishandi said:

well, ashamed to say it im fermenting a little over 2 gallons in a mr. beer keg. i dont have access to a hydrometer. i used 2 cans mr beer malt extract, 1/2 cup of browm sugar, 1/2 oz. goldings pellet hops, and the mr. beer yeast. also, i just tossed the hops in with no bag, and dont plan on filtering. according to the mr beer yeast, it said proper ferm temps were between 68 to 76. why should i not try and get it a little warmer? do u have any expierience with mr beer or this problem?

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Don't be ashamed...you are making beer....you know about out mr beer thread don't you??? There's a lot of good tips and stuff in there...

https://www.homebrewtalk.com/f39/mr-beer-read-all-about-ask-questions-46360/

In your case without a hydrometer...just walk away from it for at least 2 straight weeks (3-4 is better)...that way you will gaurentee it will be finished...and the yyeast will cleanup after itself...

Don't worry about "signs of fermentation" on the mr beer..it's difficult to tell. I did the same thing with my first beer and mr beer brew...I saew what you saw, thought something was wrong and added more yeat...when really everything was fine...

So just relax, and do some reading for the next week or so...

btw, the last beer i made in my mr beer, which was my first, was the standard west coast pale ale which has nearly 1/2 the amount of fermentable sugars in it. this beer started fermenting generally around the same time as my porter, but didnt have nearly as much foam or activity. but the activity that was going on lasted about 7 days. i fermented that beer for 12 days then bottled.

dogfishandi said:

btw, the last beer i made in my mr beer, which was my first, was the standard west coast pale ale which has nearly 1/2 the amount of fermentable sugars in it. this beer started fermenting generally around the same time as my porter, but didnt have nearly as much foam or activity. but the activity that was going on lasted about 7 days. i fermented that beer for 12 days then bottled.

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Since you are dealing with yeasts, which are living organisms there is a huge wild card factor..meaning no two fermentations are ever the same..so comparing or trying to compare one to another is really useless...think of yeasties as wives or children and you will realize that it is pointless to pin them down...that it's best to just trust everything is all right..

It usually is...

thanks a lot, i tend to sweat the small stuff sometimes and you definately gave me a lot of reassurance. ill definately let you know how it turns out. have you ever brewed any big beers in a mr beer?, im wondering if it could hold the pressure. i def trust your wisdom with ur 9000+ posts. god damn!

dogfishandi said:

thanks a lot, i tend to sweat the small stuff sometimes and you definately gave me a lot of reassurance. ill definately let you know how it turns out. have you ever brewed any big beers in a mr beer?, im wondering if it could hold the pressure. i def trust your wisdom with ur 9000+ posts. god damn!

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Yeah I've brewed some smallbatch all grain recipes in there (info in that thread)...the only problem is with no airlock setup (just the weired top) is that you could have a really active fermentation and maybe have some stuff leak through..but I haven't yet...

Just to show you...you want cool temps when you ferment...it's exothermic, so it's always going to run hotter by 5-10 degrees than ambient temp...

My current batch wrapped up fermentation in about three days. Starting gravity when it went in on Sunday was 1.052 and now it's at 1.012 on Wednesday. It bubbled like crazy on Monday afternoon and slowly tapered off after that. That said, I'm going to keep it in the tank until Saturday - the only day I can bottle it.

are those temp strips you stick on the outside of your fermentor telling you the temp of the wort itself or the ambient temp?

dogfishandi said:

are those temp strips you stick on the outside of your fermentor telling you the temp of the wort itself or the ambient temp?

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We generally tend to believe that it is the wort at the point of contact with the wall of the bucket at the point it connects with ambient air....some more anal brewers stick probes in the center of their wort during fermentation..but most of us just go by the fact that it is between 5-10 degrees hotter inside the bucket or carboy....

Revvy said:

We generally tend to believe that it is the wort at the point of contact with the wall of the bucket at the point it connects with ambient air....some more anal brewers stick probes in the center of their wort during fermentation..but most of us just go by the fact that it is between 5-10 degrees hotter inside the bucket or carboy....

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5 to 10 hotter than what a liquid crystal thermometer stuck to the side of the fermenting vessel reads? Not likely. Every time I read or hear about someone measuring the outside of a carboy vs the center, the difference is negligible.

remilard said:

5 to 10 hotter than what a liquid crystal thermometer stuck to the side of the fermenting vessel reads? Not likely. Every time I read or hear about someone measuring the outside of a carboy vs the center, the difference is negligible.

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AHem...

It apples for beers as well...

The by-products of primary fermentation are aromas and flavours, the gas carbon dioxide, and heat. The production of heat during fermentation (i.e. it is an exothermic process) means that during fermentation the temperature of the fermentation vessel will rise, and will require action on the part of the winemaker to cool it down. White fermentation is usually conducted in the range of 8-19OC, and red wine fermentions typically are allowed to run at between 25 and 32oC. At temperatures higher than this, there can be a loss of desirable aroma and flavour compounds, and unattractive aroma characters in the spectrum of caramel, burnt or cooked characters can be produced.

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Fermentation is exothermic (it produces heat). If the vessel is small enough (high surface to volume ratio), heat will be easily dissipated. Otherwise, temperature must be monitored or else it may rise too much. This is especially true at the beginning of fermentation, when it is very active.

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It's even talked about in fuel for ethanol production, even though taste profiles obviously aren't a priority like it is with beer/wine/liquor production.

Temperature effects in ethanol fermentation high corn Media

SpringerLink - Journal Article

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And from our own members..

Yuri_Rage said:

I've seen as much as 8°F above ambient in a very active fermenter.

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flyangler18 said:

+1. Some strains just go gang-busters.

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menschmaschine said:

If you take some small pieces of bubble wrap and use several layers as insulation to tape a thermometer to the outside of the fermenter, you can get a pretty good approximation of the fermentation temperature.

The degree of difference between ambient temp and fermentation temp is usually anywhere between a "few" degrees to 10 °F or more, but it depends on many variables (yeast strain, how vigorous the fermentation is, fermentation point-in-time, thermal mass of fermenter, etc). So, it's difficult to calculate a number of degrees.

Also, the fermentation temp you're shooting for depends on yeast strain and what you want in the final beer (flavor-active compounds). Generally, cleaner beers ferment on the lower and of the yeast's optimal fermentation temp range and more "flavorful" beers ferment on the higher end.

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Yuri_Rage said:

I usually keep the ambient temp 5°F below my desired fermentation temp.

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These two back me up....he even kept a temp log...

vespa2t said:

Yeah, the yeast itself generates heat, so the temp is always higher in the center of the wort. When I posted yesterday I was showing 64 on the outside of my primary, and 68 inside. This morning it is still reading 64 on the outside, but now is 70 on the inside. I have a thermometer that sticks into the wort from the lid of my primary. I think most others just keep in mind that the temp is higher inside and adjust accordingly from exterior temps.

Just something to keep in mind on the next batch. My first two batches were not good, and I attributed it to the fact that I didnt even check temps. I probably had 80-85 deg internal temps on those

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vespa2t said:

just and update this morning on how temp can be different.

My therm on the outside of the primary is now reading 65. Internal is 74. Delta is 9 deg f. between the middle and outside.

stats so far (first temp is outside of primary, second is internal, third is delta):
today
65 74 9

24 hours ago
64 72 8

48 hours ago
64 68 4

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So you can believe what you want, but a lot of us err on the side of caution....and even if we're wrong, we aren't driving the temp of our fermentation higher than necessary...

What kind of off flavors are you talking about and what kind of high temps? I had about a 1/2 day of 77 deg on day 1 of active fermentation.

thun00 said:

What kind of off flavors are you talking about and what kind of high temps? I had about a 1/2 day of 77 deg on day 1 of active fermentation.

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If I tell you you will get all nervous and panic

Remember beer is very forgiving and it depends on your yeasts...but sometimes you can get bubblegum, or banana, clove or a hot alcohol taste...They are called Phenols and Esters

BUT sometimes it's desirable..Like with Belgian Yeasts.....I'm making a belgian ale that I put a ceramic heater in front of during the first 12 hours because in my loft I can't GET the temp into the 70's that the yeast called for...


But BEFORE you get all noobishly twigged out about it...please read this thread, I tell a story and other's do too...

https://www.homebrewtalk.com/f39/ne...virtue-time-heals-all-things-even-beer-73254/

It's bound to happen on occasion, especially in warm climates, but one of the highest areas of popularity of homebrewing happens to be in the Tropic zone of AUstralia...so if they can make their beers turn out, so can we...

thun00 said:

What kind of off flavors are you talking about and what kind of high temps? I had about a 1/2 day of 77 deg on day 1 of active fermentation.

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Fusel alcohols, which give the beer a harsh alcoholic taste, as well as esters which give the beer a noticeable fruitiness (mainly isoamyl acetate, which tastes kinda like overripe bananas - this is what makes hefeweizens taste like banana but it's not appropriate for most styles). The yeast will always produce some esters during fermentation but they usually do some cleanup afterwards that lowers the levels of these back down.

77 probably won't be a problem, but upper 60's would be ideal. The only time I ever had an issue with this was with a milk stout that fermented in the mid 80's because of problems beyond my control. It came out fine except for a bit of an alcohol taste that did not belong.

In fact, for the first year or so that I was brewing I did not have the means to get my fermentation temperatures below the mid 70's, and I never got any off-flavors from this except for that milk stout.

A stick-on thermometer on a fermentation vessel in a room at 62 degrees is not going to read 62 degrees if fermentation is happening; it will read warmer.

If you are employing a swamp cooler or similar such device to keep fermentation temps, then the LC thermometer should be accurately reflecting the temperature in the vessel as equilibrium is reached.

Revvy said:

AHem...

It apples for beers as well...





It's even talked about in fuel for ethanol production, even though taste profiles obviously aren't a priority like it is with beer/wine/liquor production.



And from our own members..










These two back me up....he even kept a temp log...







So you can believe what you want, but a lot of us err on the side of caution....and even if we're wrong, we aren't driving the temp of our fermentation higher than necessary...

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None of those people back you up. The side of the carboy is not the ambient air.

Do you think that the temperature varies within the volume of fermenting beer during active fermentation? If not, why would you think the fermenting vessel could possible be 10 degrees different than the liquid touching it?

I don't "believe" anything, I measure. I just wonder why you want to believe something that nobody has measured, because it doesn't happen, so badly that you tried to refute my claim that the vessel and liquid were nearly the same temperature with a bunch of quotes comparing the liquid temperature to the ambient air.

remilard said:

None of those people back you up. The side of the carboy is not the ambient air.

Do you think that the temperature varies within the volume of fermenting beer during active fermentation? If not, why would you think the fermenting vessel could possible be 10 degrees different than the liquid touching it?

I don't "believe" anything, I measure. I just wonder why you want to believe something that nobody has measured, because it doesn't happen, so badly that you tried to refute my claim that the vessel and liquid were nearly the same temperature with a bunch of quotes comparing the liquid temperature to the ambient air.

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So how does this not back me up that the core is WARMER than the sticker?

vespa2t said:

Yeah, the yeast itself generates heat, so the temp is always higher in the center of the wort. When I posted yesterday I was showing 64 on the outside of my primary, and 68 inside. This morning it is still reading 64 on the outside, but now is 70 on the inside. I have a thermometer that sticks into the wort from the lid of my primary. I think most others just keep in mind that the temp is higher inside and adjust accordingly from exterior temps.

Just something to keep in mind on the next batch. My first two batches were not good, and I attributed it to the fact that I didnt even check temps. I probably had 80-85 deg internal temps on those

Click to expand...

vespa2t said:

just and update this morning on how temp can be different.

My therm on the outside of the primary is now reading 65. Internal is 74. Delta is 9 deg f. between the middle and outside.

stats so far (first temp is outside of primary, second is internal, third is delta):
today
65 74 9

24 hours ago
64 72 8

48 hours ago
64 68 4

Click to expand...

Like I said...you can believe what you want...But if you believe that it is possible...and try to keep the temp strip as cool as possible, then you don't have to WORRY about producing fuesils...Can we at least agree on that and NOT scare the Noobs further???

They have enough fears going on right now...then the semantics of this discussion.

I would be interested in hearing more about how vespa2t conducted his experiment.

https://www.homebrewtalk.com/f37/belgian-dubbel-temperature-fluctuations-88238/

Sounds like his liquid crystal thermometer may have been in contact with ice water.

He was also comparing two different thermometers and doesn't talk about checking that they measure the same or are similarly calibrated.

If I tape the thermocouple from a temp controller to the side of a fermenting better bottle with insulation over it and then stick the same thermocouple into the center of the beer, the difference is nowhere near 5 degrees. Two take away points, I am using the same thermometer for both measurements and I am insulating the thermometer on the outside in a good faith attempt to measure the outside of the vessel and not the ambient air or water or some combination thereof.

If all you can do is measure the ambient air then, sure, you should target several degrees below your desired fermentation temperature. I think all brewers can aspire to better temperature measurement than that, and hopefully better control.

remilard said:

I would be interested in hearing more about how vespa2t conducted his experiment.

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Well you can take it up with him if you want...or start another thread to discuss the merits of his research...Or prove me wrong otherwise (which I don't care about as long as the info is accurate, and then I would use it, like I have the other info in the past to calm the noobs and teach.)

Like I said earlier, can't for the sake of the nervous new brewers lurking who a) are scared of breathing on their beers let alone having hot fermentations b) don't understand HALF of what you an I are discussing (let alone a word like exothermic), can we just agree that temp control is important and leave it at that here?

Because we've literally threadjacked this thread...

Like I said, this was/is a nervous n00b thread, which I think, until you decided to debate the semantics of this with me here, was working.

And I'd like to kinda have this thread stay that way...because the OP's beer is really probably fine, and that WAS the point of this thread...

OK?



Besides what you just said?

I think all brewers can aspire to better temperature measurement than that, and hopefully better control.

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I've been saying all along...so ultimately we are in agreement over everything, BUT the semantics...and semantics are irrelevant to that statement...

Being a n00b myself, all I care about is how to interpret the sticky thermometer that is on my fermentor. Based on what I've read, it is better to err on the cool side than on the warm side. Which, is kinda ideal, since my basement keeps the fermentor at about 64 degrees. How far to err, well, I just don't have tham much control right now, so I'll not worry about it.

i definatley enjoyed reading ur debate there, pretty informative(?). so when certain yeasts and brews tell you to ferment at a certain temp, are they talking about the middle of the wort or the temp of the outside of the fermenter?

thanks again revvy for the advice. i stopped trying to heat my beer last night. it got up to 72 pretty much all last night and early this morning even though the heater was off, but still nothing changed at all. right now, its about 5pm and the temp is pretty steady at 65. im still a little nervous cause i dont see anything going on like my last brew which had a lot less fermentables. but i guess every brew is different. i just have to wait another week and a half or so, then bottle and maybe get a taste in the process.
cheers

I had a similar experience with a stout recently. Gravity's really the only way to tell.

But I wouldn't worry about it. If you have seen *some* fermentation in the beginning and it has continued to ferment, even in small, almost non-noticeable amounts, there probably isn't anything wrong. As far as I've seen that probably the case with most stouts in contrast to other beers.

Mine seemed to stop fermenting very well within 24 hours, but after a week the gravity was well within what I expected and the beer eventually turned out great.

If you're really worried, keep an eye on the gravity. Otherwise, just let it be. You're probably fine.

dogfishandi said:

i definatley enjoyed reading ur debate there, pretty informative(?). so when certain yeasts and brews tell you to ferment at a certain temp, are they talking about the middle of the wort or the temp of the outside of the fermenter?

thanks again revvy for the advice. i stopped trying to heat my beer last night. it got up to 72 pretty much all last night and early this morning even though the heater was off, but still nothing changed at all. right now, its about 5pm and the temp is pretty steady at 65. im still a little nervous cause i dont see anything going on like my last brew which had a lot less fermentables. but i guess every brew is different. i just have to wait another week and a half or so, then bottle and maybe get a taste in the process.
cheers

Click to expand...

A lot of us err on the side of temp caution...trying to shoot for a strip temp a few degrees less than what we want....UNLESS we are using some form of temp control....like a refrigerator, chest freezer of even a swamp cooler full of ice water where we are driving the temp of the liguid down...then after a while we can assume the liguid and the strip are in equalibrium...That's why a water bath is even a good idea...because the water will hold temp longer and help cushion any wild temp fluctuations....Or if you have it in a fridge you have to figure that after a few hours the fermenter and the lquid and the strip are in alignment...

But obviously that other guy disagrees...(like they say as 10 brewers a question and get 12 different answers. I'm not going to debate it here...and I'm just passing on what I was taught by many of the people on here.) )

But a mister beer is tiny...so if you had a thermometer strip on that I would say it is close...but in a 5 gallon bucket many of us err on the side of caution...I've been doing it this way for a lot of batches both in a mr beer, and in bigger fermenters..and my beers have turned out.


And to your other statement about it being different from your last batch......

One thing you HAVE to realize....you can NEVER compare one fermentation with another...even a split batch into two carboys with the same yeast will sometimes act totally different to each other...it could be any number of reasons, including a single temp degree difference....or something else we will never know..

You have to remember, as opposed to in organic chemistry, or even most cooking, the minute you pitch the yeast, you introduced a LIVING MICRO ORGANISM....you didn't just mix coolaid powder, sugar and water, you gave up control of the process to another living creature...So you introduced a "wild card" to the equation....a random factor left up to the whims of the little buggies...

Think of the yeasties as a teenager or a partner, and you will understand how powerless you are...

A lot of new brewers think THEY are in charge...they decide when they think the should rack or bottle, and they don't pay attention to whether the beer is ready for the next step...

Then they start is my beer ruined threads because the beer is not living up to THEIR expectations...it's not carbonated when THEY want it to be...or the secondary it to soon, and all of a sudden it starts another krausen (which freaks them out because they didn't see it in the bucket...now in the carboy it is scary and ugly) and the panic...or it doesn't appear to be fermenting in their primary and they want to fix it by warming it up

But the truth of the matter is, WE ARE NOT IN CHARGE...the yeasties are...all we are responsible for is building a nice clean factory (a sanitized fermenter) stocked with plenty of food and materials to work with (the wort) and then we just are supposed to step away and let them do what they've been doing since time began....

That's why you will find a lot of us don't secondary...we walk away from the fermenter for 3-4 weeks, then we bottle or keg...we let the yeasties do their job, and also something that a lot of people who secondary don't get the benefit of.....they clean up their own messes...the get rid of a lot of the byproducts of their fermentation...Palmer talks about the yeasts cleaning up after themselves in How to Brew...

SO basically a lot of us now just leave the yeas plenty of time to do their jobs...figuring a month is enough time to ferment, clean and settle, and still way within the safety window of the "dreaded boogeyman autolysis," then we just bottle or keg...

THis is a game of patience and trust.

SO again, don't compare it to your last batch...and don't worry about it...all is well.

And definitely check out the Mr Beer sticky at the top of the beginners forum...you will find a lot of good tips and info...



A lot of new brewer's thinl