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Brews & Views Bulletin Board Service * Brews and Views Archive 2003 * September 6, 2003 * CO2 fingerprint revealed? < Previous Next >

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Fredrik (62.20.8.148)
Posted on Tuesday, August 05, 2003 - 06:52 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Damnit! I think I found something really interesting when analyzing the CO2 logger data last night that if I am right may confirm the ideas about enzyme switching. Moreover my fermentation, that fermented like CRAZY for 24 hours went into the wall and got stuck at about 75% of the process @ 1.023!! :) :) What is even better is that I think I am on the tracks why. I have two small dips in activity before the stuck, and I know the logger well enough to tell that those dips are real, they are no artifact due to pressure or temperatures. The position of the dips as well as the position of where the fermentation got stuck is very much consistent wich the points were you would except the enzyme switches from mono, di and trisaccharides! There is no way in hell I would have found these dips with hydrometer readings :) I am going to analyze it further tonight. My theory is that the fermentation is stuck at the di to tri switch. For some reason the yeast was unable to activated the proper enzymes. Then the next question is why. Considering I was overpitching a little, perhaps only budding yeasts are flexible enough to swap between sugars? This is my hypothesis and I'm going to get another pack of dry yeast today and try to activate those enzymes in the starter and see if I can get the thing going again.

It was very remarkable how it went stuck. The fermentation was crazy!! for 24 hours and then it was just like if the yeast crashed into a wall. Normally I think this crash would have been just a "dip", but for some reasonn the yeast never recovered from the dip.

I am so excited about my first stuck fermentation. I'll be sure to analyze it to death though once I'm this lucky :) :)

/Fredrik
 

Brandon Dachel (63.238.222.190)
Posted on Tuesday, August 05, 2003 - 11:25 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Fredik I think the yeast is onto you and just trying to confuse you. :)
 

David Woods (63.95.170.150)
Posted on Tuesday, August 05, 2003 - 12:22 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Stop me if I am wrong, but I thought the MASH had the enzymes and the yeast just ferment (read eat) the sugars as they get to them. The more simple sugars first, then on to the more complex. When they (the yeast) tire out, they will leave the more complex sugars that they could not eat, including dextrins which they cannot process which leads to mouthfeel or "viscocity" of the finished product.

Without more knowledge, I would assume you are mashing too high, maybe without knowing that you are and maybe expecting too much from your yeast.

David
 

Fredrik (62.20.8.148)
Posted on Tuesday, August 05, 2003 - 12:53 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

There are different enzymes everywhere. The enzymes active in mashing are different that those active in fermentation. All enzymes are important. Though you could be right about mashing too high though!? This shows the need for a mashing model. Without knowing the exact sugar profile it's alot of guessing. I sure doesn't have a clue what exact sugar profile I got from my mashing :) and this sure is annoying.

Yeast can absorb glucose directly. Glucose enters the cell by a passive transport mechanism requiring no energy from the cell. Then it enters directly in the glycolysis which turns it into pyruvic acid.

Sucrose, maltose and maltotriose though each require their own set of enzymes. Also they have different and more complicated transport mechanisms to enter the cell than glucose. Sucrose is split by invertase enzyme into glucose and fructose, maltose is split by maltase into two glucose. Maltotriase is split by maltotriase into maltose and glucose. If for some reason that enzyme fails to be syntesised yeast will be unable to ferment that sugar. I wonder what the requirements for the enzyme switches are. This I think would be the key to resolve this.

/Fredrik
 

Andrew Pearce (216.160.193.235)
Posted on Tuesday, August 05, 2003 - 01:48 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Is anyone else besides me worried that Fredrik may fall into the wrong hands?

Stay curious, buddy.

--Andrew
 

Jeff McClain (137.201.242.130)
Posted on Tuesday, August 05, 2003 - 02:20 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Aye, Andrew. The dark side can surely sense his power in the modeling force. I only hope he is strong enough to resist it when he finds out Louis Pasteur is his FATHER!

"Fredrick....sssss-hhhaaaa.....sssss-hhhaaa...I'm your Father, Fredrick. ssss-hhhaaa...stretch out to the modeling force. ssss-hhhaaa...you know it to be true"


Grin. Actually, I'm a little bit interested in this, as I've had a couple brews stuck at 1.017 for a week now and they just won't go any lower. The OG wasn't that high, and there appears to be plenty of yeast, and the ferement started out very well. Now I'm tempted to go get some dry yeast and see if the "young" yeast (monosomthingorother) will snap it out of it. I also started this with a starter, and maybe all the young ones had permutated into old ones with cancer (is that what you are saying, Fredrick) in the original starter and couldn't finish the job. All I know is that I'm doing a black butte porter this weekend, and I'm going straight from an XL slap pack into 2 5 gallon carboys on it with no starter...see how that goes.

-Jeff
 

Jeff McClain (137.201.242.130)
Posted on Tuesday, August 05, 2003 - 02:22 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

One other question, Fredrick...how are you monitoring the fermentation? Through your microscope? You mention you would not have caught these "dips" with a hydrometer...

Just curious.

Oh no...now I'M FALLING FOR THE DARK SIDE!

-Jeff
 

Mark Tigges (66.38.134.9)
Posted on Tuesday, August 05, 2003 - 04:14 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Jeff,

See this thread:

http://hbd.org/discus/messages/1/17136.html?1058384957

I love your posts Fredrik. Keep it up.
 

JimTanguay (67.24.226.4)
Posted on Tuesday, August 05, 2003 - 04:41 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I think I am with David. You mash tempature if i remember correctly was like 167 F What you have left is dextrins that the yeast cannot burn. Now you could add amyalse to break those down if you wanted to play with enzymes.
 

chumley (199.92.192.126)
Posted on Tuesday, August 05, 2003 - 10:27 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Fredrick, you're in luck. Rob Moline just announced in today's HBD that a living yeast god, Dr. Clayton Cone, will be answering all questions pertaining to yeast posted on the HBD. Go to the last post:

http://hbd.org/hbd/CurrentHBD.html
 

David Woods (67.242.35.141)
Posted on Wednesday, August 06, 2003 - 12:13 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Fredrik,
You say that enzymes are everywhere, then why do we mash for 1-1.25 hours? I thought that was where the enzymes broke down the more complex sugars with alpha and beta something enzymes. My former homebrew bible (Homebreweing for Dummies) says nothing aboout enzymes in the fermentation.

So I went to grab THE BOOK before I posted this note. BREWING LAGER BEER, by Gregory J. Noonan says A LOT about enzymes in fermentation! He does say that it has to happen before the sugar is absorbed into the yeast cell, but I didn't find out where these enzymes come from or from where they supposedly originate in the wort.

So now I am curouis too, Fredrik. You play the devil's advocate.
 

Bret Mayden (66.210.167.82)
Posted on Wednesday, August 06, 2003 - 01:03 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

"I am so excited about my first stuck fermentation."
How many of us HBers ever said THAT?!

"This shows the need for a mashing model."
Yup, it shore does! But what would he/she look like?
 

Bret Mayden (66.210.167.82)
Posted on Wednesday, August 06, 2003 - 01:07 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Fredrik, my jibes aside, I am waiting somewhat anxiously to see where this investigation of yours leads you. Your posts, to me, are the most interesting on the board right now!
 

gregory gettman (209.66.128.130)
Posted on Wednesday, August 06, 2003 - 01:34 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

bret hurry up an buy him a ring!

Actually my freinds think I'm the brew guru but this guy takes the cake, keep it up Fredrik!!
 

Bret Mayden (66.210.167.82)
Posted on Wednesday, August 06, 2003 - 01:57 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Add an "a" to his name, and I think the board would be clogged with marriage proposals....
 

ChuckV (66.88.132.194)
Posted on Wednesday, August 06, 2003 - 02:50 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Sounds interesting Fredrik!

Is this the first time that you've seen two distinct dips in the CO2 fingerprint? Or do they appear in every fermentation at approximately the same points of attenuation progress?
 

Fredrik (213.114.44.237)
Posted on Wednesday, August 06, 2003 - 05:57 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

David, you're right that mashing breaks down starch into more simple sugars. But in fermentation they must be breakend down further before entering glycolysis. The enzymes available in fermentation are syntesised by the yeast itself as far as I know. But in order to do that yeast probably needs aminocids and there may be more constraints I have not idea about. And in some cases yeast own activation of the enzymes is inhibited or decreased. Yeast own enzymes can breakd down no bigger than trisaccharides, that's why we mash as the malt is mostly starch from the beginning.

I found an interesting abstract from MBAA that claims that increasing pitching rates leades to decreased enzyme activity of particularly maltose and maltotriase.

http://www.mbaa.com/techquarterly/abstracts/1973/tq73ab17.htm

The abstract doesn't however reveal if how significant this decrease is.

I was in hurry the yeasterday when pasting the data from the multiple runs as I had to reboot the PC from a crash. So on closer look I think there appears to be one significant dip. However since this is only my second run with the CO2 logger I have not yet acquired any statistics over more batches. However when I look at my very first CO2 graph I made (my first batch) with totally manual readings. Interestingly enough I do see a similar indication to a dip around that place! But since that is a manual bubble reading it doesn't have near the resolution of my logger. With manual reading you typically never see any interesting details. My idea is that the dip _could_ be depletion of glucose (a small dip/lag due to activation of enzymes?), but perhaps there is something else that is even more interesting. But it reamains to see what I find in the next batches! I will pay extra attention to any dips in the future. I will certainly log every single batch I make from now on.

In the future I may try to add two data channels. Temperautre and airpressure, but for now I will try to handle those factors manually.

I am a little bit confused about my stuck ferment. Considering my nice starter - if it can't digest maltotriose which is one theory, it must be damn sensitive and I imagine that this would happen to alot of people all the time? One the other hand, if mashing made lots of unfermentables, it would be the best explanation. But it seems strange to me that my mashing was THAT extreme?

Has anyone else of you ever have a high FG that you are sure is due to the mashing?

I put some yeast in half the batch, and the other half is not on secondary. My problem is I had no maltotrise, so I took some of the wort and boiled off the alcohol, added a little tiny bit of sucrose and used that to activated a pack of dry yeast. I'll see if something happens in there.

I WANT to believe that it was my mashing.

I realise that if I am going to do some serious progress in the yeast quest I can't measure of worts with unknown sugar profile. Until I've got a mashing model I consider doing some extract brews. With the extracts you always know the sugar profile from the data sheet of the manufacturer.

If I can actually detect dips that are enzyme switches. I could even use the CO2 logger to determine the sugar profile of the wort. There are some other small dips in the graph, but without more data from more batches they are possibly uncertain. But who knows, if they keep coming at the same place in the coming batches there is something there.

1

2

/Fredrik
 

Fredrik (213.114.44.237)
Posted on Wednesday, August 06, 2003 - 06:06 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Note that the first graph is a smoothed graph from manual readings. The big unceartainty in the readings in this graph was why I decided to make a logger that counted ALL bubbles, as opposed ot just a few every hour.

So the second graph is from my CO2 logger. It's the first run on a "real" batch. My first testrun was a test starter with some sucrose.

I still have some tuning to do though on the logger. But I live with it as is for awhile.

/Fredrik
 

Fredrik (62.20.8.148)
Posted on Wednesday, August 06, 2003 - 10:33 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I am at work just installed a new ftp server and think I know why my fermentation is stuck ;)

$ ftp 192.168.0.200
Connected to 192.168.0.200.
220 ProFTPD 1.2.8 Server (ProFTPD Default Installation) [SaccharomycesCerevisae.xx.se]
Name (192.168.0.200:maltotriose): maltotriose
331 Password required for maltotriose.
Password:
530 Login incorrect.
Login failed.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp>

Can anyone tell if I am obsessed with yeast?

/Fredrik
 

Jake Isaacs (128.163.110.72)
Posted on Wednesday, August 06, 2003 - 03:58 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

While enzymes aren't necessarily "everywhere", they are certainly ubiquitous in living things. I suppose there is some misunderstanding of what an enzyme is.

Put simply, it's a protein that performs chemistry. A protein is essentially a chain of amino acids that folds up into a characteristic shape. The fold of an enzyme is such that a particular region forms a binding surface specific for certain molecules (be they small like sugars or large like other proteins). Part of this binding surface will have interesting chemical bits sticking out that encourage a particular chemical reaction on whatever binds appropriately. The reaction might be to break something in two, join two things together, modify part of a molecule, etc.

That said, malted grains are certainly not the only place you'd find enzymes. They're in every living cell (or recently deceased, like in malt), doing the hard work that keeps you, yeast, barley, etc. alive. Of course, there are lots of other classes of proteins that make the whole show work, like the transporters Fredrik alludes to above.

This concludes the "Support Your Local Enzymes" public service announcement. Now back to your normal programming...
 

Fredrik (213.114.44.237)
Posted on Wednesday, August 06, 2003 - 05:07 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Jake! You wouldn't happen to know were to look if I want learn about the chemical properties of fermentation enzymes do you? What about CRC handbook of biochemistry and molecular biology? I have been considering it but I suspect it may be disappointing - I recently got CRC handbook of chemistry and physics 64ed from ebay, and I must say I was a little disappointed to find that maltotriose wasn't even listed among the organic compounds. What kind of a table is that?? Could it possible be under another name? Also there was not alot of kinetics data in there, which dissapointed me.

/Fredrik
 

Jake Isaacs (128.163.110.72)
Posted on Wednesday, August 06, 2003 - 05:55 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I'm not really sure what you mean by "chemical properties". That covers quite a bit of ground. CRC handbooks probably aren't going to be all that useful for the kind of modeling that I've seen you discuss.

There are a lot of textbooks on yeast metabolism, but I'm not familiar enough to recommend any. That type of resource as well as the primary literature are probably your best bets for yeast enzyme kinetic parameters and whatnot. Also keep in mind that fermentation kinetics are going to be very dependent on the yeast strain.

There are quite a few experts on the hbd mailing list that don't frequent the forums, so you might want to ask some questions there. I confess that I'm not sure what you're proposing is doable or useful, but have fun trying!
 

Denny Conn (140.211.82.4)
Posted on Wednesday, August 06, 2003 - 07:11 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Fredrik, you are ready for the next step in your search for knowledge. Go to www.hbd.org and sign up for the digest. Post your questions for Dr. Cone and the rest of the collective minds. I think you'll get more of the kind of answers you're looking for there than you do here. (no offense intended, anyone!) Really...do it!
 

Hophead (167.4.1.38)
Posted on Wednesday, August 06, 2003 - 09:05 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Great, now I get to see this irrelevant-techno-babble-BS on another forum. Thanks DC. :)

"I'm not sure what you're proposing is doable or useful"

PERFECT.
 

Denny Conn (140.211.82.4)
Posted on Wednesday, August 06, 2003 - 09:15 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

"I'm not sure what you're proposing is doable or useful" Ditto here...but maybe there will be less posts here once Fredrik realizes those guys know more than we do! :)
 

Adam W (128.125.6.113)
Posted on Wednesday, August 06, 2003 - 10:05 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I for one find it amusing that Fredrik has spent so much energy on a can of Coopers (see first graph), not that there is anything wrong with that....

Allow another scientist to pipe in here:

Enzymes allow thermodynamically unfavorable reactions to occur more efficiently (broad characterization). Many reactions that are facilitated by enzymes will occur naturally, albeit at a much slower rate.

Correct me if I am wrong, but Fredrik didn't state what kind of yeast he used. If this is a yeast that has been repitched several times then the stuck fermentation may be due to genetic selection issues (i.e. a mutation).
 

ChuckV (66.88.132.194)
Posted on Wednesday, August 06, 2003 - 10:36 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

There are too many uncontrolled variables and not enough repeat data to really make any scientific assumptions at this point. You've made one logger run and noticed 1 dip. You will need to repeat the experiment: the mash, pitch volume, starter wort conditions, age of and strain of yeast must also be identical to your first logger test. Fredrick, perhaps you could follow your idea of using extracts for testing the logger, that way you have eliminated a few mashing variables. Once you've held the variables as constant as you can and have several repeat fingerprints that can be shown to have similarities, then we can make assumptions.

On another note, you may want to contact someone in the UC Davis fermentation sciences department and see if they are willing to talk with you. I'm sure that they will have all the information you need as well as give you some suggestions. Have you used PubMed at all to locate journals?
 

don price (65.32.41.81)
Posted on Thursday, August 07, 2003 - 01:16 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Excellent discussion. Nice to know that there is plenty of brewing stuff to mess with and learn about later. But I think I'll keep the brewing simple for the rest of the year and focus on building some more furniture.

Go Fredrik!

Don
 

Fredrik (213.114.44.237)
Posted on Thursday, August 07, 2003 - 01:42 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Ok, I may try posting some on the list. I've been subscribing for it for awhile but never posted there though. The news bout Dr. Cone is cool, it'll be interesting to see :)

For me this quest has more than one dimension. It's more than just revealing the "truth" of fermentation and yeast. I enjoy and study the learning process of equal order. By studying any learning process you can learn something deeper. To me science is not assembling unquestionable facts and models, science is the dynamic process of bringing order and sense out of the unknown in the "best" way, while the "facts" keep changing! There is no such thing as complete knowledge and the task of making the best assumptions out of incomplete knowledge is interesting. And in this context, this all wouldn't have been as interesting if I had have had a background in microbiology. I honestly understand those of you that are microbiologists by profession that wouldn't even bother with a model. If I was a microbiologist I am sure I would model something else. By the same logic I would never ever turn my dearest hobby into a profession. Philosphy of natural sciences and physics is my fave topic, but there is no way in hell I would do that kind of thinking on a commercial basis.

Adam, the yeast I used was 11g windor lallemand dry yeast, that I made a two step starter out of.

1. +50% cell count increase + aeration
2. +50% cell count increase + aeration

I aerated the starter by shaking 3-4 tims an hour for the first hours. I did lots of shaking!! This was the most important point.

Ended up with approx 500e9 cells for 18 liter batch - as determined by microscope.

Why did I do a starter out of dry yeast??

1. I though one pack was a little low and my LHBS was closed for vacation.

2. I wanted to do the count experiment in the microscope. (I wouldn't do a plain batch without throwing in at least one experiment each time:)

3. I wanted to make sure the yeast was active, full of sterols and glycogen. According to my understanding so far. I also wanted to practice making a good starter.

Does anyone see I missed something? At least to my current understanding, this would be a good starter?

Chuck I agree I need more data. It's coming, sooner or later. I can't help getting excited about my first runs though! :)

I have contacted a professor at my local university, as they have an awesome fermentation lab with all the damn measurement gages an analysis you can imagine. But he said he had no personal experience with anaerobic processes and forwared my request, but not surprisingly I didn't reveice any information. Those guys seems busy with their own research and educating students. Why would they waste time educating someone who is not even a student, and even worse, give away useful information? I don't blame them because with some exceptions that's the way it seems to work in that world.

/Fredrik
 

Ken Anderson (24.55.254.125)
Posted on Thursday, August 07, 2003 - 03:23 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Maybe you're not a student now, but if I may ask, where did you get your education? You sound like a really knowledgeable guy, Fredrik.
Ken A.
 

Fredrik (62.20.8.148)
Posted on Thursday, August 07, 2003 - 07:42 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I studied at Uppsala university which was nice. But I didn't study any biology or biochemistry, just mathematics, physics and some comp sci. I had early plans for researching in physics as a profession but I came to my senses in good time and realized that I was not willing to compromise. I had very specific ideas of what I want to do and how and that I believe in and I don't accept anyone to tweak those by paying me. I belive that for various reasons not even a professor has free hands. As soon as you get payed doing something chances are you get tied up. This I wouldn't want for my dearest hobbies. Maybe for my second or third dearest hobby. I work with measurement technology, data acquisition and computers. This is very nice but nothing that rates as any priorities in life, so I don't mind getting payed to do it.

/Fredrik
 

Fredrik (213.114.44.237)
Posted on Saturday, August 09, 2003 - 06:45 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I am still confused why my damn batch got stuck at 49% app att. I am getting more convinced that it is my mahsing that for some reason gave me only about 40% extract fermentability. I am doing some testing on the beer. And I won't give up until I ruled out the possibiliyu that there are still fermentables in the beer.

Considering I did a good starter, well aerated, and pitch 2.5 million cells / ml / plato - how likely is it that an all malt wort gets stuck?

I wont give up this until I know beyond reasonable doubt what in the devil that caused the fermentation to get stuck!

Currently, I think the most likely cause is my mashing. But I don't consider it beyond any reasonable doubt yet. My knowledge is too poor.

What do you guys think? Do you think my mashing could make as low as 40% fermentables?? Is it _possible_?

/Fredrik
 

Fredrik (62.20.8.148)
Posted on Wednesday, August 13, 2003 - 08:15 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I have been obsessed with so many details lately that I may have actually missed some obvious important things, like the choice of strain :) I just checked John Palmers page and his description of the windsor lallemand is

" Attenuation and flocculation are medium-low."

This in combination with my mashing may together provide the explanation. I was doubtful that the mashing alone would be the explanation. Perhaps it leaves most of the maltotriose and then things suddenly start to make alot more sense.

I will probably do a small scale test with the same yeast with extract - just for comparing. But in the next full size batch I will switch to Nottingham Ale (Lallemand). In the experiments it is very nice to use dry yeast because it's cheap and the initial state of the yeast is probably more defined.

Nottingham ale is described to be

"..neutral ale yeast with lower levels of esters and a crisp, malty finish."
"...High attenuation and medium-high flocculation."

"..57-70°F"

This seems to be an ideal dry yeast for me.

/Fredrik
 

Bill Pierce (24.141.63.119)
Posted on Wednesday, August 13, 2003 - 02:00 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I recommend Danstar Nottingham as a neutral ale yeast. It is very similar to Wyeast 1056/White Labs WLP001 and more convenient because there is no need to make a starter (assuming that you pitch a couple of packets into a 5 gallon batch). Some people call this strain "boring" but sometimes the goal is little if any flavor contribution from the yeast.
 

Fredrik (62.20.8.148)
Posted on Wednesday, August 13, 2003 - 02:20 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Good to see you are back Bill!

I do a small starter even with dry yeast. Not to increase the cell count(for that reason I could take another pack) but to make sure it's really going and healthy before I pitch it. I don't know what kind of sterol and glycogen levels you can expect to dry yeast. Glycogen may probably deplete with age? "Sterols" I don't know? So making two small stepups with lots of aeration will I think cure this? what do you think?

Hey Bill, can I have your opinion about my mashing in this thread? Could this mashing (see pic) possibly give 40% fermentables due to excessive dextrins? I failed to keep the temp exactly constant becuase during the rest.

It was 50/50 munich and pale alt malt and some 7% crystal.

picdd

/Fredrik
 

Fredrik (62.20.8.148)
Posted on Wednesday, August 13, 2003 - 02:28 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Same problem.

http://hem.bredband.net/frerad/beer/5/mask.jpg

/Fredrik
 

Bill Pierce (24.141.63.119)
Posted on Wednesday, August 13, 2003 - 02:55 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Fredrik, the mash did not spend much time above 65 C (149 F) which would account for relatively low efficiency but not low apparent attenuation. I would expect higher attenuation but there are likely other factors at work in this case.
 

Fredrik (62.20.8.148)
Posted on Wednesday, August 13, 2003 - 03:15 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Hmmm... thanks Bill! This weekend I'll do a plain extract brew using only DME. I will have the data sheet of the DME so there is no question what's in there and what fermentability of the wort is. But I'll try another yeast that are more attenuative and that I would suppose can eat maltotriose. If I still get these problems there must be something with my understanding of yeast or something else I missed. I will also taste the "stuck" beer this weekend and investigate the foam stability which will be interesting.

I have tried mashing now, but now I will postpone it and use only DME with known sugar profile until I know exactly what is going on and the modell is done.

/Fredrik
 

Fredrik (62.20.8.148)
Posted on Friday, August 22, 2003 - 08:02 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

My stuck fermentation has been bothering me! Damnit I haven't found any causes so far. My mashing may now have been perferct but I do not think it was THAT bad. Also, I just refuse to think the starter was wrong!! In fact I think it was pretty damn good. Last night I even started to wonder if the devil was involved.

But now I just came to think of another possible explanation. As I mentioned before I hope going to get a fridge soon. But meanwhile I've been fermenting in my computer room leaving the fermentor right at the air conditioning unit.

But now it just realized that this fact probably puts the fermentor on some heavy temperature stress. The temperature of the cooling air is just 15C. Given the fermentor is in equilibrium it's 18C of the room temp is 22C. But during krasen the temp inside will be bigger, and possibly the yeast circulation hitting the cold fermentor wall gets knocked out. I think this stupid phenomenon is my problem. Because even looking backwards I think I did everything else pretty optimal. Except for the temperature control of course. What I seem to have missed is that although the temperature of the wort is good, the fermentor walls may be several degrees lower, knocking the yeast out.

This is the most likely explanation I have found so far and I think this is it. This was kind of stupid, but for some reason I didn't think of this before. Slap me hard please!!!! I am a moron!!

What do you guys think? :)

/Fredrik

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