why slow start of fermentation?

[j.postema]

Hi all,

last wednesday I prepared a new batch of mead. Because starting gravity appeared too low, the next day I added honey. That day s.g. was abount 1,092. I used wild-flower honey and 'gereral' wine-yeast. I didn't boil the water / honey, just heated it a little bit to help dissolve. I added only 3 cutted raisins and some dead yeast as nutrient.
I rehydrated the yeast before pitching and assured that wort temperature was ok.

After 3 days (saturday) there was almost no airlock activity and only a very small decrease in s.g.: about 1,090. The bottle was in a room with a temperature between 14-18 degrees Celcius. Sunday during the day I put the bottle in the (warmer) livingroom because I thought that temperature could be the problem, but nothing changed. I prepared a starter (1 cup of wort, rehydrated yeast) at a warm termperature for about 10 hours before pitching. This morning I added the starter and tonight I see that bubble activity increases: at the moment 1 bubble per 135 sec.!

The problem is that I lack a room with constant temperature. During the night temperature drops to (just a guess) about 15 gegrees Celcius. During the day it's about 19-21 degrees Celcius.

As I changed two things at the same time (added starter / extra yeast, raised temperature)
I don't know what caused the fermentation to start, but I expect it is the higher temperature. My question is: is it very bad to have changing temperatures? (day / night)
And would it for the next batch be better to start with a higher (+/- 21 degrees Celcisus) temperature the first days just to help start the fermentation, and later when it is fermenting put the carboy in a lower temperature? (as I planned a slow fermentation I want the carboy in a temperature of about 15 degrees Celcius)

 

[WRATHWILDE]

The Temperature swings aren't helping your yeast. 15(c) will really slow down the fermentation. Did you oxygenate your must? Your yeast may not have had enough oxygen to propagate to the extent needed for a healthy fermentation. Also if you could be more specific with the type of yeast you used it would be helpful. 19(c) to 20(c) is a good range for most yeasts.

if you can't stabilize the temperature of your brewing room, you may want to wrap your carboy in a blanket to help keep the heat in and the cold out.

Cheers,
Jered Talbot
(Wrathwilde)

 

[j.postema]

Hi,

thanks for your answer. I don't know exactly what type of yeast it is, it's just what I found in the refrigerator. My dad used it for his wine and it should be a general wine yeast for wines with upt to 18% alcohol, temp. range of 5-30 degrees Celcius.

I did wrap the carboy in a blanket and I aerated twice a day by shaking the carboy for 5 minutes. I think I will keep the carboy in the livingroom as temperatures are during the day around 68 (F) instead of the colder room (59 - 64 F).

By the way, bubble activity has increased to 1 bubble per 35 sec.!

 

[j.postema]

Hi all,

bubble activity increased to +/- 1 bubble per 10 sec, so I think the problem is solved!

 

[Dan McFeeley]

Glad to hear the fermentation seems to be underway.

Another thought on how the problem could have started -- adding honey to a fermenting honey must where the yeasties had already adjusted to the original starting gravity could have been an additional factor in why they went dormant.

Also, it's important to have the temperature of the honey must and of the rehydrated yeast or starter solution fairly close. Can't recall the specific range at the moment, but I think it's not much more than 10 degrees C. Maybe some with a better memory or a good reference at hand can chip in on this.

Different yeast strains will have varying temperature ranges at which they best function. Some can handle temperatures dipping down into the 50's F, some will slow down and maybe even stall. It's probably difficult to tell here, since you were saying that this was a general wine yeast your father was using, but it probably wasn't labeled or marked as to what yeast strain it was?

 

[j.postema]

Hi McFeeley,

thanks for your reply. I didn't realize that adding new honey one day after pitching the yeast could be a factor...

Yes indeed, unfortunately the yeast wasn't labeled, I was also wandering what yeast strain it was. The only thing I know is that it was bought at a local DIY wine / beer / cheese shop, maybe I will ask them if they can tell me more about it.

I just had a look at the mead, and some bubbles with a small amount of foam have appeared.

 

[j.postema]

Hi all,

fermenting looks fine, but I still have a few newbee-questions... Bubble activity is still about 11 bubbles per second, when I read the forum or watch movies of yeasting mead, I see rates of 2 bubbles per second. Does that mean that my fermentation is (too) slow? Or shouldn't I only check bubble-rate but gravity as well?

An if so, I didn't measure gravity because of the risk of oxidation... I have to open the carboy and siphon a small amount of wort for measuring, and I read that it was advisable to not put back this wort because that would stimulate oxidation. My batch is only about 4 liters so I don't want to lose too much of my mead. Or would it be better to put the hydrometer permanently in the carboy during first fermentation?

And one last question: in the newbee guide I read the following:

"The end of the Lag phase is marked by the formation of Krausen, a layer of foam on top of the Must. At this point, the addition of some nutrients may be beneficial."

Yesterday there appeared the foam on the must, so I would like to add some extra nutrients (raisins). Am I too late if I add these nutrients 2 days after foam has appeared?

Thanks in advance!

 

[lastbornjoker]

hello postema
i may be able to help a little. First of bubble rate is a really poor way to tell how ur fermention is going. use ur hydrometer for that it is by far one of the most useful tools for the home brewer/maker.
as far as oxidation i dont "think" u have to worry about that untill after 1/3 sugar break. If u need more info on that do a search and u will bring up more than u want to know lol

good luck

edit as long as u sanitize everthing getting samples to check gravity is fine some people will even put them back but some frown on that practice. u may want to get u a wine theft and about leaving the hydrometer in the carboy It may get bublle stuck to it causing inacurate readings alltho ive done it many times lol

 

[j.postema]

Hi lastbornjoker,

thanks for your reply, it was of help!

 

[Medsen Fey]

Bubble rates are highly inaccurate. I just had a batch that fermented to completion and hardly had a bubble (I've got a bucket with a bit if a leak I'm afraid, but I'm not losing any sleep over it). If a yeast is a slow fermenter, the rate will be slow even if the fermentation is healthy.

Using a hydrometer will give you the most accurate results so that you can monitor progress. You can take a gravity with a wine thief and then let it drain back in without undue oxygenation. Oxygenation becomes more of a problem after fermentation is finished and it is not producing a blanket of CO2.

Some folks do not like to put samples taken into a wine thief and touched by a hydrometer back in. This may reduce the risk of contamination a little, but I don't think it makes much difference. Of more importance, many folks like to taste the mead that is sampled - this gives an idea of how it is progressing and may give you sensory data that you act on in terms of additions to the must.

I can understand not wanting to take out many samples from a 1 gallon batch because it will all be sampled away. That is one reason why I rarely make anything less than 3 gallons. Another way to avoid over-sampling is to use a refractometer instead of a hydrometer to track the progress of fermentation. Yet another alternative is to monitor progress by weight change with a postal scale. There is a good thread on this by Dan McFeeley.

Airlocks are fun to watch (which kinda tells you how much excitement I have going on) but they don't tell you much.

Good Mazing!
Medsen

 

[j.postema]

Hi Medsen,

thanks for your reply! I just measured gravity and s.g. is only about 1.082. Starting gravity (10 days ago) was 1.092, so I suppose fermentation is too slow, although I see lots of small CO2 bubbles in the mead and airlockactivity is about 1 bubble per 10 seconds.

I'm wondering what to do next: should I aerate the mead again, twice a day, because 1/3 sugar-break still isn't reached? (I suppose 1/3 sugar-break is at 0.66 * (1.092 - 1.008 (semi-sweet mead)) = 1,055 s.g.?

I aerated only the first 3 days according to the newbee-guide, but I think I made a mistake by not measuring gravity

By the way, I think temperature is okay: 21 (C), and unfortunately I'm not able to measure pH level.

 

[fatbloke]

I shouldn't think that you'd need to be too anal about the exact numbers i.e. 1090(ish) to 1000(ish) is about 90, hence the 1/3 break would be in the region of 1060.

I doubt that it'd matter if the must had reached something between 1055 and 1065 or so.

One of the reasons, when I make a batch, that I mix the must and before pitching the yeast, I take a jug full and put it in a sanitised liquidiser and give it a whiz.

That (so far) has meant that I don't need to worry too much about frequent aeration.

Of course, if you were making some with a high starting gravity then it might be different. On those occasions I'd think it necessary to give the yeast every bit of help that you could.....

regards

fatbloke

 

[Medsen Fey]

Fatbloke is right - as long as your gravity is somewhere close, you are okay when it comes to additions.

I think checking your pH would be very helpful. I suspect that may be why you are getting sluggish performance, but I hesitate to suggest adding some potassium bicarbonate or calcium carbonate without knowing what the pH reading is.

 

[j.postema]

Hi,

thanks for the replies. I will buy a pH-test set a.s.a.p., maybe pH is low...

By the way, I made another batch, Joe's ancient orange mead. It still took 1 day for this batch to start bubbling, but after 1 day there was a lot of CO2 production compared to the first batch, about 1 bubble / 5 sec. and there were also larger bubbles at the top surface, so at least it is much more active than the first batch.

I will post the pH measurement results here as soon as I bought the pH test set. One other question about my first (slow fermening) batch: I added raisins for nutrient 19 days ago. Should I remove them by racking the mead to prevent them giving a raisin taste to the mead? Or can I just leave them in the mead?

By the way, currently I am consuming my first (1 liter) batch which is made of only unknown type honey, (out of date / expired) bread yeast and just tap water. Although it is only 7 weeks old, it tastes very good in my opinion. At least I like it very much and my dad likes it as well!

 

[j.postema]

Hi,

it appeared that my dad had some paper pH test strips left, which I used for testing. Range was 5.5 to 3.8 in steps of 0.3 and if I interpreted the colors correct, the mead had a pH of 3.8.

I also measured gravity, it was 1.070. The mead tasted very sweet and I didn't taste any alcohol.

I'm wondering if pH is okay? I dont know the problem, temperature is about 20 degrees (C). My other batches have no problems... Is it the lack of right nutrients? I added dead yeast cells, used dark wild flower honey, added raisins. Did aeration during first 3 days.

 

[fatbloke]

Hi,

it appeared that my dad had some paper pH test strips left, which I used for testing. Range was 5.5 to 3.8 in steps of 0.3 and if I interpreted the colors correct, the mead had a pH of 3.8.

I also measured gravity, it was 1.070. The mead tasted very sweet and I didn't taste any alcohol.

I'm wondering if pH is okay? I dont know the problem, temperature is about 20 degrees (C). My other batches have no problems... Is it the lack of right nutrients? I added dead yeast cells, used dark wild flower honey, added raisins. Did aeration during first 3 days.

honey is famously low in nutrients. I'd guess that there would be some in the raisins and the yeast hulls, but if you can get some proprietary nutrient i.e. one that has an ingredients listing (the Brouwland stuff should have - it's sold in the EU etc etc), you'd see that there's a lot more to nutrient than just hull's and nitrogen.

I'd say that while I like my pH to be between 3.2 and 3.5, 3.8 isn't exactly that far off is it (there's a "school of thought" that says anything is fine as long as it's below neutral i.e. 7.0 and then you can adjust the acid prior to bottling).

So if it's still showing quite high sugar (gravity) after this amount of time, then maybe it's time to try nutrient. I'd think something like half of whatever the recommended dosage is on the package. Then you should (in theory) see some improvement, but not use enough nutrient to cause any "off flavours".

regards

fatbloke

 

[j.postema]

Hi Fatbloke,

thanks for your reply. I found two things in the refrigerator: one called "Pecto-enzyme" and another called "super yeast nutrient nutrient". I suppose I should use the last one? On the label is printed:

Contains: ammoniumphosphates, vit. B1, minerals, dietary minerals. Dosage: 2-3 grams / 10 liter. For fast fermentation and for restarting fermentation again.

 

[j.postema]

It appeared that the box was empty. Today I went to the store and bought some nutrient and added it to the mead. I also put it next to the central-heating so temperature is about 20 degrees (C). I'm curious if fermentation will improve soon...

 

[Medsen Fey]

Where is the gravity currently?

The higher temp and the nutrients may help get it moving along, but I am still suspicious of the pH. If your paper's range is 3.8 to 5 and you are getting 3.8, the pH could be 2.8. If you can borrow a pH meter and get a good reading you may find a simple cure.

On the other hand, if you are like me and want to rush in where angels fear to tread, you could add in 1 gram of potassium bicarbonate or calcium carbonate just to see if it helps.

Endeavor to persevere!
Medsen

 

[fatbloke]

Hi Fatbloke,

thanks for your reply. I found two things in the refrigerator: one called "Pecto-enzyme" and another called "super yeast nutrient nutrient". I suppose I should use the last one? On the label is printed:

Contains: ammoniumphosphates, vit. B1, minerals, dietary minerals. Dosage: 2-3 grams / 10 liter. For fast fermentation and for restarting fermentation again.

Yes, that'd be the one, though as you say in the subsequent post - the box was empty. Bummer!

Where is the gravity currently?

The higher temp and the nutrients may help get it moving along, but I am still suspicious of the pH. If your paper's range is 3.8 to 5 and you are getting 3.8, the pH could be 2.8. If you can borrow a pH meter and get a good reading you may find a simple cure.

On the other hand, if you are like me and want to rush in where angels fear to tread, you could add in 1 gram of potassium bicarbonate or calcium carbonate just to see if it helps.

Endeavor to persevere!
Medsen

Oh! now I hadn't thought of that one. Of course, if the strips are only for a set/specific reading then they might well just show the lowest level of colour change if it's below that.

Well spotted sherlock 8) getting a pH meter is an outstanding suggestion. It should give j.postema an accurate idea of what's going on - plus it'd be handy for further batches of whatever i.e. meads/wines/beers etc.

Mead makers of the world unite;D

regards

fatbloke