Fermentation hasn't started. Suggestions?

[pweis909]

Here's the situation:

Day 1: I made 5 gallons of must for melomel. In addition to pasteurized cherry juice and canned raspberry and blackberry fruit puree, I added frozen blueberries. Because of the blueberries, I sulfited the must according to instructions on a bottle of potassium metabisulfite.
Day 2:I pitched 20 grams of hydrated Lalvin Narbonne yeast. I oxygenated with a blast of pure O2 through an airstone (for about 1 minute, which is what I do with beers...) at the time of pitching and added 3/4 tsp of yeast energizer. Day 3: No activity, so I aerated and pitched more energizer.
Day 4 (today): Still no airlock activity or signs of fermentation. I took a hydrometer sample and gravity is still at 1.090.

Fermenter temperature has been 68-70 the whole time.

Where does the problem lie? What's the solution?
-Do I just need to be more patient?
-Is it possible that the sulfite had not evolved from the must before I pitched and killed or suppressed the yeast? It's only my 4th mead and I never sulfited before. Maybe I needed to be much more vigorous in aearation to lose the residual sulfite?
- Should I get more yeast and repitch?
- Is pH an issue?

Suggestions, guidance appreciation. Thanks.
Peter

 

[wayneb]

In the absence of any additional information, I'd recommend that you double check the labeling on the packaging from that cherry juice. Are you absolutely sure that it is preservative-free? I've had "100% natural" juices before that say only on the fine print "sorbates" or "benzoate" added. If true, you may have a must that will not support yeast cell division.

Also, what exactly were the instructions on your source of metabisulfite? How much did you add, and to what total volume of must?

One final note - pH could indeed be an issue. Depending on the acid additions from all of those juices/fruits, you may be below a point where the yeast can take off. Can you measure pH, and if so, what is it?

Oh, and Welcome to "Gotmead," BTW!!

 

[wayneb]

One additional thought. Sulfite, if it is the problem, will dissipate naturally with time. So all you may have to do is to wait long enough for the free SO2 level to fall below 50 ppm, and then you can re-pitch with a freshly hydrated batch of 71B. That could take as little as a couple of days, depending on the size of your original sulfite dose.

 

[pweis909]

Thanks for the reply.

The cherry juice was Indian Summer brand (Montmorency). I used 1.13 gallons juice to a total of 5 gallons must (including fruit volume). The juice label says that it is pasteurized but does not say that it has sorbate or benzoate or any other preservative. Elsewhere on the net, I see that someone describes using it to make wine, so I think I'm OK on that front. I would be really bummed, having been burned once before by not reading the fine print about sodium benzoate on some pasteurized apple cider.

The potassium metabislufite instructions say 1/4 tsp per 5 gallons.

I checked the pH with pH paper strips. Not the most accurate, perhaps, but what’s available. pH~4.2

 

[wayneb]

OK - so we'll rule out sorbates/benzoate as a possibility. If your pH measurement is in the middle of the range of your strips, then it can be pretty accurate (depending on how good your color vision is), but if you are near the edges of the range (high or low), or if your pH strips are older and have been exposed to air for some months, then there can be lots of uncertainty using the strips. Nevertheless, your pH does not appear to be at a point where it could be a problem.

At your pH, the amount of K-metabisulfite you added to your 5 gallon volume is enough to supply about 50-60 ppm free SO2 in a must that doesn't readily bind it. Since you have some dark red juices in there, some of that SO2 would have been bound shortly after the addition. So the SO2 level in the must wasn't at a level that normally attenuates commercial yeast strains. You're sure that you measured 1/4 tsp, and not 1/2 tsp or 1/4 tbsp? I know, but I have to ask the obvious to make sure we've covered all the possibilities. One other possibility - did you mix up a stronger than usual sanitizer to clean everything before you started this batch?

You have a perplexing one here! ;D

So if it isn't preservative based, and it isn't pH, and it isn't from the K-meta addition, and we can rule out equipment/sanitizer toxicity... then what's left is either: 1) Temperature differential between the rehydrated yeast and the must at pitching, or 2) You got some yeast that had not been handled carefully prior to purchase or is too old to be viable, or 3) You left the rehydrated yeast too long before pitching it.

Concerning #1, did you take care to pitch only when the temperature differential between your rehydrated yeast and your must was 10 degrees or less? Significant temperature differentials can stunt, or even kill, your yeast.

Relevant to #2, it is rare, but I've gotten packs of Active Dry Yeast from my LHBS in years past that were no longer viable.

Finally, concerning #3, if you left your yeast in the rehydration medium for too long before pitching (30 minutes is the usually recommended max time), it will start to die from starvation. Yeast need the sugars in the must pretty much by the time they've completed the rehydration interval (about 10-15 minutes) or they get stressed.

At this point all I can recommend is to get some more yeast, rehydrate it per the manufacturer's directions, and then to be sure it is good to go, "proof" it by adding some fermentable sugar and seeing if it starts to produce any CO2 after 30 minutes or so. Then pitch the new yeast and hopefully things will take off.

 

[Medsen Fey]

Wayne's advice is good. I'll go a bit further and say rehydrate the yeast and then add a small amount (1/4 cup) of your must to make sure that the yeast is acclimating to it. Build it up as a starter with subsequent must additions, and then pitch it. That should guarantee that it goes.

 

[pweis909]

You have me second guessing myself on the K-metabisulfite. Could I have accidentally used 1/2 tsp instead of 1 quarter? I don't think so, but if that's the case, I would have a longer wait for the SO2 to exit. Do you expect after 4 days, SO2 will be at sub-lethal levels, assuming a 1/2 tsp dose?

The temperature differential is possible. The yeast instructions were to rehydrate at a higher temp than I would have guessed (100-110 F or thereabouts), and the must was 70 F. I waited 15 minutes and pitched, so maybe shocked the yeast. Damn.

Off to the shop for some more 71B. Just a question of how soon to wait to repitch (in case I did blow it with the K-metabisulfite). At this point, it's an expensive little mead; hope it doesn't go down the drain.

 

[Medsen Fey]

Just aerate the must well. After 4 days and a good aeration, it should be okay. Of course you can always use a test kit to measure the sulfite.

Again, if you use the must to acclimate the yeast, when it is bubbling, you'll know the yeast can tolerate whatever level happens to be present.

 

[wayneb]

I agree with Medsen - aerate well and residual SO2 should no longer be a problem. The amount of free SO2 in a must tends to fall off roughly exponentially, so after 4 days you've lost a lot already to the airspace in the neck of your carboy (assuming you're using a carboy and not a bucket - if primary is in a bucket, even more has likely escaped).

From your description I more suspect that the temperature differential is what has done in your yeast, the first time out. As Medsen suggests, if you add a bit of your must to the rehydrated yeast (about half as much must as your rehydrated liquid volume is generally what I do), then you will both temperature acclimate your yeast and provide them with some of the must to proof-test at the same time.

 

[pweis909]

Followed Wayne's and Medsen's advice. Added some must to newly hydrated yeast. Yeast looked VERY happy when I repitched. Fingers crossed, but very appreciative of your collective guidance.

Peter

 

[Dwhite]

I'm curious about this one.

What's happened?

Inquiring minds..........


All the Best,
D. White

 

[pweis909]

My fermentation took off after following the advice given. Which brings me to my next questions....

I was thinking that once the fermentation starts, I can relax. After two days, the airlock stops bubbling, and the mead smells pretty rank. Very vegetal, kind of cabbage-like. So I start snooping around on the net and I come across an article on melomels written by Curt Stock. I actually read this when it came out in BYO, but forgot about it until now.

What I learn is that punching down the cap can avoid off flavors that can ruin a melomel. Punching down the cap can help dissipate CO2 and heat that might harm the yeast. I didn't do any cap punching, until today, three days into the real fermentation. Gravity has dropped from 1.090 to 1.040. The mead tastes OK to me, but the smell is off-putting.

I don't have a degassing attachment for a drill motor, so all I really did for cap-punching was stir for about 2 minutes with a sanitize spoon. As all the fruit swirled around, the mead foamed as I learned to expect. The temperature dropped from 79F to 77 F over the course of several hours. I stirred 2x more today, at approximately 6 hour intervals. The most recent time, I got noticeably less foam.

Am I managing this OK? Any more suggestions?

 

[Medsen Fey]

Vegetal cabbage-like smells suggest the production of H2S or related sulfur compounds. This can be indicative of yeast stress and nutrient deficiency. 79F is higher than I like to let most yeast ferment and could be contributing as well.

Even though you are past the 1/2 way point I would aerate it really well to blow off some of that smell and I'd add more yeast energizer [5 grams of Fermaid 2133 (or GoFerm) and perhaps a couple of grams of Fermaid K would be my approach]

Hopefully that will eliminate the odor.

Medsen

 

[pweis909]

Temperature Stress: I thought red wine yeast liked it this warm. I can back it down 5 degrees or so by moving to my cellar. But I just wired a temperature controller that is yet to be tested. What temp should I shoot for? I have a spare freezer.... And how gradual should I be about lowering it?

Oxygen Stress: I'll have to rely on the shaking or stirring approach. My airstone blew off to the the bottom of my fermenter when I tried to oxygen last. It did start out with a good amount, but I realize I should ideally be oxygenating through most of primary.

Nutrient Stress: I'm afraid all I have available is DAP and yeast energizer (LDCarlson packaged - contains DAP, Yeast hulls, MgSO4, and Vitamin B complex). My local supplier is pretty good for a backwater town, but does not have everything. No Fermaid K. How does that stuff differ, anyhow?

Well, I'm doing the best I can, and that seemed to result in drinkable meads in my three previous, primative efforts. I guess I'll have to cross my fingers on this one.

BTW, should I keep stirring that cap down?

 

[Medsen Fey]

There are pluses and minus to the higher temps. They increase color extraction and tannin extraction, and may give somewhat less "fruit pop" aroma and flavor. However, it can cause undernourished yeast to get stinky (and in some cases, even well nourished ones). I'd probably shoot for keeping it in the lower 70s.

Yeast really don't assimilated DAP well late in the fermentation. They can still take up amino nitrogen and products like Fermaid 2133, Fermaid O, yeast extract, or the rehydration formula GoFerm are all made without DAP. The yeast energizer you have has a mixture, and will probably be good to use, and the B vitamins are helpful to prevent H2S. I'd add about 4 grams (around 1 tsp) ASAP.

You don't need a fancy air stone. Just open the mead to air and stir/swirl it aerate it well. Normally we encourage aeration of the must daily during the first few days, or until the 1/3 fermentation point. After that time, it usually is not helpful but if you get sulfur smells, it is wise to aerate as this will help eliminate them.

Throughout the fermentation it is good to punch down (or swirl down) the cap at least twice a day. This prevents the cap from drying out and harboring spoilage organisms and improves extraction. It also helps keep the yeast up in suspension where they can be most active.

I hope that helps.

Medsen

 

[pweis909]

Well, your advice makes sense to me. Whether it helps with the mead will require patience.

It appears to have dropped another 10 points today, so from 1.090 to 1.030. There is still a bit of cabbage to it though.

BTW, any idea how much attenuation I should hope for? If I should be aerating until the last third of fermentation, I need to have a sense for how far the yeast (71B) would normally go. I may very well be in the last third now. I don't see a % attenuation listed at the Lalvin website like I am accustomed to seeing at Wyeast and White Labs (at least for beer yeast).

 

[akueck]

Wine yeast doesn't come with % attenuation because the assumption is 100%, up to the tolerance level. A lot of factors will move the actual tolerance level up or down, such as pitch rate, oxygenation, nitrogen concentration, etc. Complex sugars will drive down the attenuation as well, but grape musts are 100% fermentable so the manufacturers don't worry about that either. (Honey musts are 100% fermentable too. Braggots are probably the only place to worry about long-chain sugars.)

71B is listed to 14% but can be nudged to at least 17% in some cases. Your OG of 1.090 is low enough that you should probably expect a FG near 1.000.

 

[Medsen Fey]

The aeration is normally done during the first 1/3 of fermentation only. In your case, since the sulfur smell is still there, even though you're in the later part of fermentation I'd aerate and use the nutrients as mentioned previously. Usually that will clear the odor within 24-36 hours.

You can safely figure with wines/meads that your fermentation will be limited by the alcohol tolerance of the yeast, not by attenuation. With your batch it really should finish with a gravity below 1.000.

 

[pweis909]

Latest concern: oxidation?

The advise on my fermentation odor issue seems to have worked. My melomel has fermented down to 1.002. The cabbage odors are gone, I think. The hydrometer sample tasted very tart, with a slight amount of bitterness that reminds me of the pith of a citrus peel. Something extracted from the fruit, maybe?

Working with that thought, I decided it was time to get this off all that fruit and I racked this to a 5 gallon glass carboy. However, because of all that fruit, I only moved about 4-4.5 gallons of liquid. What do you guys recommend doing about all that headspace in the carboy?

One thought I have is to mix up a mini-must using just honey and water, no fruit. If use that to top off the head space, am I inviting other problems? Re-fermentation and clogged airlocks, for example. I wouldn't mind a sweeter melomel, so am also thinking I could mix up a mini-must but add K-sorbate to prevent further fermentation. But it seems too early to kill the yeast, who probably have other things to do yet, like clean up a bunch of fermentation by-products.

No further action until I get some advice. Grateful for all the help so far!
Peter

 

[wayneb]

If you don't mind restarting the fermentation for a bit, the simple honey-water topping off liquid would work just fine. At this stage in fermentation, you won't re-awaken Mt. Meadsuvius; it will just start up and percolate slowly until the additional sugars from the new honey are used up, or you reach the ethanol tolerance of your yeast.

If you decide to use this to backsweeten, then I'd recommend using both potassium sorbate as well as a 75-100ppm dose of metabisulfite, to avoid encouraging the growth of malolactic bacteria. ML bacteria, if not killed off by the sulfite, will metabolize potassium sorbate into geraniol, which is the stuff that gives wilting geraniums their peculiarly pungent, and not attractive, odor. (It also reminds me of citronella - yuk!)