View Full Version : First infection

02-01-2011, 11:16 PM
Well, as I have said a couple times I have been brewing beer for quite awhile and am now trying my hand at mead.

Never had an infection batch of beer. Aside from the argument that there are always some wild yeast/bacteria present.

But I think I got one on my first mead. Used Lalvin 71B. OG of 1.139 - after 9 days it is down to 1.011. So we are talking 17.25% ABV on a yeast with 14% alcohol tolerance. I have heard this yeast will go well past its tolerance but I am not too stubborn to admit that I probably have something else going to work in this batch.

Thoughts? Experiences? Really pretty bummed out about this. It seemed to be progressing quite well. Apparently a little too well.....

Chevette Girl
02-01-2011, 11:54 PM
It's possible your yeast were just really happy... have you got the recipe and procedures listed in a brewlog you can link to? If not, listing it here would help the Mead Masters figure out what might be going on.

02-02-2011, 12:00 AM
You're 99.9999% likely fine - the likelihood that something wild (read: not bred for hundreds of years to tolerate alcohol) could outstrip a wine yeast is very small in my opinion.

71B is a weird strain. I've had it go past 16%, some people say it never goes past 14% for them, and one person even claimed they got it past 20% (I think most of us guessed a math error of some kind in that case since the person would not explain their method nor their honey amounts or starting gravity vs finishing gravity, etc).

And hey - even if something wild did get in there, if it keeps tasting and smelling good, then it IS good. ;D

02-02-2011, 12:01 AM
CG's right - we need to know a bit more about what you did (process, ingredients - amounts of each as well as the list, rehydration method, temperatures, etc.) and then we can possibly help out more. But it is not uncommon to have 71B go past its nominal 14% ethanol tolerance.

Don't worry - you can wait until either it stops or goes completely dry, then you can stabilize and backsweeten the mead to taste. It really isn't difficult, and after a few months' aging I doubt if you could taste the difference between a mead that has naturally stopped at a gravity above total dryness, vs. one that had been backsweetened.

02-02-2011, 12:18 AM
Thanks guys - I am feeling a little better about it but am still not real confident. I will give you as much information as I can here and see if anything makes sense.

Here was my recipe:

18.75 pounds of berries (mostly strawberries but some blackberries, raspberries, and blueberries)
21 pounds of wildflower honey
3 gallons of spring water
10 grams of 71B (rehydrated in 25 grams go ferm)
OG 1.139
Aerated 2 minutes with direct oxygen through a stone after pitching
1 minute on day 2 and 3. Stirred/punched cap/degassed at least twice a day for first 8 days.

SNA: 4.5 grams fermaid K, 2 grams DAP on day 0,2,4 and 6

Potassium bicarbonate to keep pH around 3.6 on day 2,4,6

Let's see what else - fruit was frozen and then thawed prior to putting it in.

Not to rule it out but I feel that I have the sanitation thing down pretty good - lot's of batches of beer without issues.

Just pulled a sample and it pretty much tastes like rocket fuel - although this may be perfectly normal (and probably is) for a 9 day old mead.

I used the no heat method and no sulfites up front (although I think I will be next time).

Day 2: 1.109
Day 4: 1.070
Day 6: 1.040
Day 9: 1.011
Day 10: I am predicting 1.000

I think more than anything even if I can salvage it - it just upsets me that I planned to have it finish at like 1.025 (or 15.75% ABV) which I thought was about the peak for healthy 71B and it is not doing what I wanted it to.... aaarrrggghhh!

Anything else?

Oh yeah, it is still going I think this is going to complete dryness - 18.75% alcohol. Really is that possible?

Thanks so much!

02-02-2011, 12:26 AM
Hmmm... it looks like you may not have accounted for all the additional water that the fruit would have added. Unless you smashed the thawed fruit completely, and then pressed the liquid out from the pulp, it is very likely that your measurement of OG didn't yet have all the fruit water in the mix.

Fruit generally are 80 to 90% liquid, and that is usually only around an SG of 1.040-1.060. The addition of so much fruit to your batch undoubtedly diluted your honey more than you think. I doubt that you're up as high as 18.75% ABV... from my back of the envelope calculations, it looks to me that you might be more in the 16.5 to 17% range. That's still a healthy dose of ethanol, but it is significantly less than you were thinking and it is within the capability of 71B in a properly managed fermentation.

CONGRATULATIONS! You managed this ferment very well! ;)

Oh, and the likelihood of contamination in anything that high in ethanol content is almost vanishingly small. No wild yeast that I've ever seen has taken any of my batches anywhere near that high of an alcohol content, and that much ethanol usually kills most spoilage organisms.

02-02-2011, 12:28 AM
It's highly unlikely that it'll go that far, but it was pretty unlikely to get to where it is already!

I wouldn't worry at all. What's done is done - contamination is a difficult thing to happen, and if it did happen, and it happened to be by a yeast/bacteria that can go to 17.5% ABV then all you can do is hope it'll still be tasty.

It's possible you were contaminated, but it seems much much more likely to me that 71B simply went that far.

Wait till it finishes fermenting, follow normal racking and aging proceedures (don't leave it too long on 71B lees, they are not good for lees aging) and see how it does. I'm betting it'll have some burn from the ABV for a year or two, but other than that (and possibly needing some backsweetening) will be fine.

EDIT: and as Wayne says (darn, I should have caught that!) it's likely your SG was actually lower than your reading due to fruit juice still trapped in the fruit. As they broke down and released juice your SG would have dropped as well. Still high ABV though, but it means you're definitely within the range of ABV that 71B can pull off.

Shadar Aman
02-02-2011, 12:29 AM
Sounds like you may have been TOO nice to that yeast. :P

Are there actually spoilage organisms (other than acetobacter) that could survive that much alchohol? If it were wild yeast, that wouldn't really count as an infection in my book, just an unexpected twist.

02-02-2011, 12:48 AM
Thanks again - this is good stuff. So what would you predict that my actual OG was? Is the calculator on this site any good? What do you guys use?

I just took another run at using it and if I assume that I got 1.5 gallons of water out of the berries (is that reasonable for 18.75 pounds) then I would have had a total volume of 6.25 gallons. 3 water + 1.75 honey + 1.5 from berries. Plugging this in gives me an estimated OG of 1.130 instead of 1.139. Does this seem right? Then I would be around 16% right now and possibly headed for 17.5%.

I am also interested in Shadar's comment about whether any spoilage organisms other than acetobacter can survive at 16%.

Wayne, I am just a little confused by "Fruit generally are 80 to 90% liquid, and that is usually only around an SG of 1.040-1.060". Does this mean fruits give out different amounts of water at different gravities? Can you help me understand what you are saying since I am pretty sure that is not it.

Thanks guys. I appreciate the help.

Shadar Aman
02-02-2011, 12:57 AM
Wayne, I am just a little confused by "Fruit generally are 80 to 90% liquid, and that is usually only around an SG of 1.040-1.060". Does this mean fruits give out different amounts of water at different gravities? Can you help me understand what you are saying since I am pretty sure that is not it.

I think (and I could be wrong) he's saying that fruit juice (the part of the fruit that stays in your mead) is around 1.040-1.060. So that 80-90% liquid is lower gravity than the must you've added it to.

02-02-2011, 01:00 PM
What I meant to say was that fruit can be thought of as consisting of liquid (water plus dissolved solids, primarily sugars) and solid matter. Most of the volume of any typical fruit is that sugar-infused water component. The insoluble solids (plant cellulose primarily) are a smaller fraction of the total volume. Each specific fruit is of course different in water and sugar content, and there are also differences between ripe and unripe fruit, but for estimation purposes you can use 80% and 1.050 as rough approximations of the amount of liquid that you derive from your fruit, and the SG of that liquid.

There used to be a great table of fruit water and sugar content out on the web, but I can't seem to find it anymore -- too much wordy drivel about dieting and the like to sort through now. Maybe Medsen knows where it is; if he does I'm sure he'll chime in with a link.

But, regardless of the actual values, if you make a simple assumption that 80% of your fruit (by weight) is water containing dissolved sugars, with the liquid at around a net specific gravity of 1.050, then your 18.75 lbs of fruit yields around 15 lbs (6.8 Kg) of liquid. Pure water weighs very close to one kilogram per liter, or around 3.785 kilograms per gallon. A liquid that has a specific gravity of 1.050 weighs 1.050 x 3.785 = 3.975 Kg per gallon. That means your 6.8 Kg of fruit liquid was approximately 6.8/3.975 = 1.71 gallons in volume.

You can now use the equation S1*V1 + S2*V2 = St*Vt to figure out what the net specific gravity of your mixture is. You have 21 lbs of wildflower honey dissolved in 3 gallons of water. That should be an SG of around 1.155. So, for this case, S1 = 1.155 and V1 = 4.8, S2 = 1.050 and V2 = 1.71, and since Vt = V1 + V2, Vt = 6.51 gallons.

Then (1.155*4.8 + 1.050*1.71)/6.51 = 1.127, and that's the net SG of your must with the fruit added. Now this is a very rough approximation, based on some wild assumptions about the water and sugar content of your fruit, but it is likely to be closer to actual than your first measured SG, since there would have been a lot of that fruit liquid still trapped in the fruit when you first made the measurement.

If a must at OG of 1.127 ferments to complete dryness, that would yield an ABV of around 17%.

02-02-2011, 01:42 PM
Great advice everyone, I'm learning a lot by reading this post. One thing I'll chime in on: If you happen to have both a refractometer and a hydrometer, you can take a reading of both when it finishes fermenting and figure out what the actual starting gravity was by using some calculators that are available online.

Also, I've heard of Brett infecting 13% wines, but I'm not sure about above 16%. It would likely take a pretty long time to ferment anything, so I guess it is not a very likely culprit.

02-02-2011, 03:51 PM
Yes, this has turned into a great thread hasn't it. I was just thinking that not only am I getting some of my questions answered but I bet people are learning a lot from this post.

May be a little more for the "intermediate" meadmaker at this point (or at least intermediate fermentation knowledge) but great nonetheless. I will most definitely keep everyone posted on where this finishes and how it turns out a ways down the road.

Big thanks to everyone. I think this thread and Wayne's last post specifically convinced me that I need to become a patron and support this site!

Medsen Fey
02-02-2011, 10:22 PM
The brsquared site has some detailed fruit information (http://www.brsquared.org/wine/CalcInfo/FruitDat.htm) including juice yield (reported as cc/Kg). For the berries you are typically looking a 500-550, which would suggest around 1.25 gallons (usually I'd guess about 14 pounds per gallon - or around 1.4 gallons in this case). However, the gravity of berry juice is probably not going to be higher than 1.035, so Wayne's number is still a pretty good guesstimate.

02-02-2011, 11:20 PM
That's the one I was lookin' for! Thanks, Medsen!

Medsen Fey
02-03-2011, 11:25 AM
I am also interested in Shadar's comment about whether any spoilage organisms other than acetobacter can survive at 16%.

Lactobacillus Trichodes can survive at 18%, Zygosaccharomyces Bailii has been documented in 21% ABV IIRC. So yes, there are spoilage organisms (including others) that can survive high alcohol but they are not common.

You probably don't have a spoilage organism or wild yeast. What you have is either 71B which has gone above and beyond the call of duty (which can happen) or you picked up a high ABV strain from your brewing area that floated in and has grown and taken over. Have you been using any Champagne yeast in prior batches?

02-03-2011, 02:49 PM
Thanks Medsen. No, I have not been using any champagne yeasts. I am pretty new to making mead (been brewing beer for awhile). The bucket that this is fermenting in was actually brand new so I washed/sanitized it - point is nothing from previous batches of anything in there.

Where would these spoilage organisms come from the honey? Fruit?

I am thinking that this 71B just is very healthy at this point. It is slowed way down. I am thinking it is not going to finish much below the 1.011 it was at a couple days ago. I will post it when I take another sample on Sunday.

Take a look at this article:


This was done by a meadmaker from my area (St. Paul) and a very good, knowledgable one at that.

Although it does not say so specifically it sure looks like he used 71B in his tests here and took this one over 18% alcohol. Not sure if Kris is on here or not but he could certainly chime in if he is.

Thoughts from anyone on this?

02-03-2011, 05:52 PM
I agree with your conclusion. Your 71B simply outperformed its rated ethanol tolerance by a few percent, primarily because you managed the fermentation so well. It is now settling down and it may end up leaving this batch close to where you wanted it to finish (albeit at a slightly higher ethanol level) to begin with.

However, just because it slows to an apparent stop now, doesn't mean that after a racking it won't start back up again. Many meadmakers have been surprised by bottle bombs from semi-sweet to sweet meads that they've bottled after they assumed that fermentation was over. If you ever bottle a mead semi-sweet to sweet, even if all fermentation has appeared to have stopped, stabilize the mead with sulphite and potassium sorbate first.

02-03-2011, 06:14 PM
BTW, Kris has been on Gotmead in the past, but he hasn't been a regular contributor. I think that he supplies most of his meadmaking wisdom to those who frequent the Northern Brewer forum. BTW - he and I have some differences of opinion regarding some aspects of the meadmaking (and aging) process, but from what I've been able to determine, they're for the most part really just different variations on a mostly common theme.

02-04-2011, 12:01 AM
Thanks Wayne,

Like you said you and Kris have differences of opinion and that is probably just that. Both of you have a great deal of knowledge and experience which undoubtedly will lead to that. More than one way to skin a cat....

So, I am going to take your advice on bottle bombs to heart because the though of them scares the heck out of me. I have heard of people getting real hurt. Never had one with beer (knock on wood) but probably only bottle about every fifth batch.

So, obviously I have never done the whole stabilizing thing. Have read and researched quite a bit about it but never actually done it. So, my primary is a 7.9 gallon bucket. I am going to siphon into a 5 gallon glass carboy and should fill it up (which I believe is actually about 5.4 gallons. Do I rack onto the sulphites? If so, how much. Do I need to mix it in? What is the best way to mix (this or sorbate or honey for backsweetening) without introducing oxygen? How long do you wait before adding the sorbate (and how much)? Do you mix this in with sterile water before adding? Pull a bit of the mead to mix with? How long does it take sorbate to be effective before backsweetening? I assume there are a lot of ways to backsweeten but honey is the "preferred" method?

Also, I read something about that you should clarify before sulphiting/stabilizing. Is there any truth to this? I do not plan to filter at least no yet so it would have to be bentonite or isinglass or something. Should you rack onto this then rerack onto sulphite? I just don't like to transfer so much with the risk of introducing oxygen.

Obviously a lot of questions but help on any or all of them is much appreciated. Thanks!

02-04-2011, 12:13 AM
When I stabilize as part of the process of racking (as you plan on doing), I'll first dissolve my metabisulphite dose in a little distilled water, and pour it into the carboy. Then I'll rack my mead over top of that. The act of racking will create enough turbulence to disperse the sulphite, and that way you don't get any additional air mixing.

When I also use sorbate (in sweet meads), I'll wait a little while (typically 4 to hours -- never more than 12), and then add the sorbate, also pre-dissolved in a little water. I'll then gently take my stir rod and slowly mix in the sorbate. I do this very gently so as to introduce the minimum possible unwanted O2.

Then I'll bottle; you can wait a little longer before bottling, but again I don't generally wait more than a few hours. You don't want the sulphite level to drop to the point where any MLF bacteria present could take root. They do a nasty number on sorbate, and produce a stinky substance called geraniol in the process. Sulphite will keep MLF bacteria at bay.

Clarifying before doing any stabilization is a good idea simply because in most meads, any haze left in the mead will to at least some extent contain yeast cells. Some of them may be active. The fewer active yeast that you transfer into the stabilization carboy, the more successful your stabilization will be.

If you're not going to filter, then yes, rack off of any fining agent and/or lees, and stabilize. I generally do this all in one step - rack off of lees into a carboy that contains my sulphite dose, etc. Generally, in any mead already in a secondary fermenter (by that I mean already racked off of the first, gross, lees), you can simply prepare the fining agent according to manufacturers directions and then just slowly stir it into the mead already in that carboy. Then wait a time sufficient for the fining agent to do its thing, and then rack onto the sulphite stabilizer.

02-04-2011, 12:37 AM
Great information - that kind of put it all together for me. So where does backsweetening come into play here I am assuming it would be after all stabilization right before bottling. If using honey is it not pretty difficult to mix it thoroughly with introducing 02? Any tips or tricks. Also, how many points does a pound of honey typically add to 5 gallons of mead?
So stabilizing is not something that needs to be done ASAP after primary fermentation huh? I mean I know that is assuming you do it since some people don't. But it is alright to age in the secondary for several months then stabilize/bottle? What are the pros/cons?
Thanks again for the information.

Medsen Fey
02-04-2011, 10:23 AM
The longer you wait, and the clearer the mead, the less likely that active yeast cells will be able to overcome the stabilizing agents.

If you do use honey to backsweeten, it will add a bit of haze that needs to clear so I wouldn't do it just before bottling as it will create some fine sediment in the bottles. Also, after backsweetening, I like to wait several weeks just to be sure that things don't start up again.

02-04-2011, 11:26 AM
I definitely understand what Medsen is saying here and agree with it in my very rookie experience level.
That said I am confused about the process when trying to backsweeten now. My understanding is that I need to stabilize before backsweetening but I should wait a while after backsweetening to clear/make sure stabilization actually worked. So do I then need to sulfite again before bottling since they would be ineffective at that point?
So the process would maybe be
1. Rack from primary to secondary for clarification
2. Rack to a third vessel to sulfite/stabilize and backsweeten
3. Rack to a bottling bucket, sulfite and bottle
Can someone critique this process?

Would this add too much sulfite or is the first dose effectively "blown off" so the level is only whatever the dose before bottling was?

Also, what is the best way to mix the honey in when backsweetening? Having never done it I am not sure but I imagine it to be difficult to mix honey in without introducting O2. Do you use a lees stirrer on a very low speed?

Thank you all!

02-04-2011, 11:41 AM
Actually, that's a good approach that you have outlined.

If you have a sulphite test kit available, you can determine exactly how much more K-Meta to add at the time of bottling. But even if you don't, you can assume that most of the free SO2 has "escaped" from your must by the time you're ready for the bottling step, so another dose of sulphite equivalent to the one that you do just prior to backsweetening, would do the trick.

Even with multiple sulphite additions done in the blind (i.e. without testing levels), you are only adding on the order of 50 to 75 ppm each time so you'd have a long ways to go before you get to what is customarily considered the detectable threshold (around 325 to 375 ppm), and that assumes all the sulphite that you add stays in your mead. In fact, it does blow off with time.

For backsweetening I usually mix a little water with my honey, which makes it very fluid and easy to mix into your must. I then hand-stir very slowly with a stir rod, and then close up the carboy with an airlock and wait for things to clear.

02-04-2011, 11:59 AM
More on backsweetening... I wrote up my procedure in more detail in another Gotmead thread a few years back. If you drill down in this thread: http://www.gotmead.com/forum/showthread.php?t=12106&highlight=backsweeten+gravity&page=2 you will find more of my thoughts on the process.

02-05-2011, 02:37 PM
Good stuff on the backsweeting Wayne. That post pretty much answers all of my questions related to that.... for now.
I am thinkin about transferring tomorrow but am wondering if I should cold crash it first. I likely have a bunch of fruit waste floating around in there in additions to the yeast (a lot of which has probably floccuated by now). I have read some posts on here related to a bunch of loss in big fruit melomels and don't want that to happen. I am at just a hair over 6 gallons in the primary right now and it has been in there for two weeks. I would like to get close to 5.5 in the secondary. Would a week or so at 54 degrees help me accomplish this? I definitely don't need to be clogging my autosiphon either.
My biggest concern is time on the yeast 71B. I gotta imagine is a bunch of yeast to get through that thing. How long is generally too long on this particular strain?

02-07-2011, 02:37 PM
Sorry for the delay - I've been away for a few days.

First, yeast autolysis is usually something that doesn't become noticeable for a couple of months - temperature of the must, pH, etc., influence autolysis rates, but to be safe with a stinker like 71B, I'd get it off the lees within a couple of months of the first racking (out of primary).

In my experience, cold crashing does help to settle out yeast (because as they go dormant, the yeast cells sink to the bottom of the carboy), but misc. "gunk" that happens to be floating in the mead doesn't usually settle any quicker at low temps.

And as long as you get through enough rackings that you don't see a substantial yeast layer at the bottom of your carboy a week or two after a given racking, then you'll be fine.

02-08-2011, 02:48 PM
OMG, Glad I read this thread..I am in the process of a Mel now..and now I will have to guess on the final ABV...lol

I made a straight mead with Raspberry and Clover honey. I waited until the fermentation was almost done in the secondary. Then I racked that mead into a carboy ontop of 9 lbs of Raspberry, Blackberry and Blueberries. The Fermentation started up again, real strong. Which I did attribute to the added fluid.

I never even thought about the the SG swing because of it..well I'll just put this on the Bottle.

ABV Above %14


02-12-2011, 10:40 AM
Wanted to give everyone who was nice enought to get involved with this thread an update. I transferred it to a secondary a few days ago for clarification. Final gravity - 1.004. So, it left just a little bit of meat on the bone.
So, that means the 71B went to somewhere right around 17%!. Assume OG of 1.129 or there abouts.
Although my mead tasting experience is very limited I have to say that it tasted pretty decent for a very young mead - quite a bit of ethanol but not overwhelming.
I am pretty sure at this point that nothing funky got in there and that it was just 71B working real hard. Like I said, not much mead tasting experience but I am a BJCP beer judge so I would like to think I would pick up any blatent, common off flavors in mead as well but maybe not.

Anyway. Will let you all know how it turns out in 6 months or so. I think I am going to backsweeten it up to about 1.025 at some point (or to taste).

Thanks for the help!