View Full Version : Air Space

09-26-2010, 01:59 PM
Greetings all.

Question #1: I bought a 132.086 gallon fermentation tank which measures 3' 3.37" long x 2' 3.55" wide x 3' 2.58." How much air space should I leave between the top of the fermenting mead and the top of the tank where the air lock is located?

Question #2: How long should the primary fermentation take for this amount of mead?

Question #3: Will one year in corked bottles be sufficient time for the mead to have aged for commercial consumption?

My mead recipe consists primarily of honey, Passion Fruit and cardamom.

Thanks for your help.

09-26-2010, 04:18 PM
Welcome to the forums......

Greetings all.

Question #1: I bought a 132.086 gallon fermentation tank which measures 3' 3.37" long x 2' 3.55" wide x 3' 2.58." How much air space should I leave between the top of the fermenting mead and the top of the tank where the air lock is located?
There's no defined limit/margin. It's just that primary fermentations are often done in buckets, because with staggered nutrient addition techniques, it's very easy to get a "mead fountain" when adding extra nutrient - which obviously causes loses (mead must and money). Once the ferment is underway and it's ready to move to secondary, then there's not usually a problem and fermenters can be filled all the way up to the neck (if using glass).

I'd have thought that if all your ingredients go in at the start then there'd be less of an issue.

What might be an issue is that is quite a large volume and whether you'd need some sort of cooling system. If you're in a hot climate, then the heat that's generated by the fermentation reaction could become an issue - hence it can vary from yeast to yeast.....

Question #2: How long should the primary fermentation take for this amount of mead? Hum ? well surely that would depend on how "balanced" the must is, you can read of some people who have fermentations that are done in a week, others for whom it can take weeks or even months. So I'd think that our more knowledgable members might need more info to have even some sort of guess.

Question #3: Will one year in corked bottles be sufficient time for the mead to have aged for commercial consumption?

My mead recipe consists primarily of honey, Passion Fruit and cardamom.

Thanks for your help.Again, there's too many variables to predict. It would depend all sorts of things, like how long it's existed outside the bottles. The recipe can create many issues, like has the ferment made a medicinal taste (Ken's analogy is "Listerine" in his book), which often ages out, over time. If you've made a batch and it's taken a long time to finish the process of clearing etc, then a year might be fine, but at the same time, it might need a lot longer.

Meads, like "grape" wines, are ready, when they're ready. There's no set minimum (or maximum for that matter).

Sorry if that's rather vague and inconclusive.........



09-26-2010, 05:34 PM

Sounds like quite a project! Have you made this mead in smaller quantities before?

Definitely look into heat dissipation. For such large volumes, the amount of heat generated is hard to remove by passive means. Cooling jackets or other system are often employed to keep the temperature from running away.

The "how much" and "how long" questions are hard to answer. If you've made this mead before, you can probably expect similar behavior now...if you can ferment it the same way. The hard part about scaling up to large volumes is keeping the process controlled. It is easy to aerate and cool a 5 gallon batch, but much more difficult for a 100 gallon batch. Before you start, I'd encourage looking into all the variables you want to control, and come up with a plan for how to control them. A predictable process leads to a predictable result, and then questions like "how much" and "how long" will be easier to answer. Good luck!

09-26-2010, 09:12 PM
Greetings and thanks to Fatbloke & akueck. Your input is greatly appreciated (and needed).

Fatbloke: Thanks for the info regarding the amount of air space. One suggestion I got was to allow 25% of the fermentation tank for air space which I thought was a waste of space that could be used for mead but, SAFETY, is a primary concern for me.

I didn't feel any warmth during the fermentation when I picked up the one gallon batch to shake/aerate. I wonder why the company who sold me the fermentation tank made no comment/suggestion regarding cooling systems? Is there a danger of the tank blowing up?

I did several one gallon test runs with different spices and honey to water ratios using Lalvin EC-1118 yeast and they all turned out pretty good. My first batch using the cardamom and Passion Fruit recipe was too strong in aroma so I cut it down by half which is nice but, recently, when I tasted the original strong batch, it had mellowed down really well, so, I'm going back to it for the BIG BATCH.

akueck: Your comments regarding heat dissipation and cooling jackets are of concern to me. Again, as I mentioned in my reply to Fatbloke above, is there a danger of the tank blowing up, especially, in summer when the temperature here in the Caribbean can reach the upper nineties with humidity factor raising to lower 100's (104 F)?

I placed all the ingredients together in the first fermentation and the yeast fermentation took about three weeks to completely die down. As I mentioned to Fatbloke, I didn't feel any heat when I shook the 1 gallon test batches. Also, hand shaking the light 1 gallon batches didn't require opening them while a 130+ gallon tank is another matter.

Regarding your aeration comment, I thought once you placed the air lock on such a large tank you aren't supposed to open it until the fermentation is complete so that no contamination with bacteria or other whatevers gets into the fermenting liquid. Should I get and extra long aerating paddle? If so, how often do I open the air lock to aerate? Once or twice a day?

Btw, my avatar is a bottle of my mead. Nice color, right?

Thanks for your feedback, guys.

09-26-2010, 09:19 PM
Btw, can I keep asking questions related to the original three in this thread, or should I search for similar related threads already in existence? Lots of meandering may require I get a boy scout and a compass in case I get lost. ;D

09-27-2010, 12:18 AM
RE: searching...yes definitely search. Not many here work with such large volumes, but some do and there are threads dealing with some of the challenges. Check out the section of the board for folks with commercial aspirations. You can also ask more questions here, but if they stray too far from the original topic it's best to put them somewhere easier to find. If you find another thread that is on topic, and not too old, feel free to post there.

I don't think you need to worry about blowing anything up. The airlock or whatever you're using should keep things from exploding. The worry about heat is that it doesn't tend to turn out a very good product. Most yeasts do best below about 75 F, and you'll start picking up off-flavors when you stray above that. Some yeast strains are ok well into the 80s, but very few will operate in the 90s and still turn out something drinkable.

My comment about "passive" cooling for small batches means that the dissipation of heat into the surrounding air is usually enough to keep the fermentation only about 5-10 degrees warmer than the room it's in. Large batches run the risk of getting hotter than that. Heat index/humidity factor is irrelevant (it affects your "perception" of temperature, but not the actual temperature), but if you're at 90 F you can bet the mead will hit 100 if you don't stop it. While that's much hotter than I'd like to operate, this is not an automatic death sentence...but I'd work out the kinks with small batches before investing in such a large batch. Typical problems you might see with such high temperature fermentations include high concentrations of fusels (aka higher alcohols) that will smell and taste a little like Listerine and often cause hangovers; excessive ester and/or phenol production, which can range from an overly fruity taste to bandaid flavor; excessive loss of aroma due to high speed fermentation; and other fun things which you can probably find by searching (high temperatures plague everyone south of the Mason-Dixon line and get discussed quite often).

As for aeration, well it depends on the specifics of your recipe. Most meads benefit from aeration during the first 1/3 of fermentation. This is not to say that not aerating causes a mead to fail, only that the aeration is beneficial. I encourage you to read through the NewBee guide (link on the left of the screen), which will go through some of the things that the folks on this board consider the "starting point" for meadmaking.

And as a general comment, I'll repeat my earlier statement about process controls. Making large volumes of mead is different than making small batches. The art of meadmaking can be worked out in small volumes, after that it becomes a feat of science/engineering. If you are planning on producing commercial scale volumes and expect consistency, you need to nail down the process variables and control them. The big variables to consider include the recipe (OG, kinds of honey, fruit, etc), temperature, aeration, nutrition, mixing, initial yeast health and pitch rate, and post-process oxygen exposure. These are all controllable variables, as long as you put in steps to do so. I hope I'm not discouraging you, I just don't want you to invest time and money into such a large project and have it come out disappointing.

PS I'm an engineer (in case you didn't get that), so I will probably harp on "process controls" more than most. I swear I'm not crazy, there are engineers in every manufacturing business whose sole purpose is to scale operations from small to big. I want you to succeed!

09-27-2010, 07:37 AM
I greatly appreciate your advice, akueck. Thanks.

Close to a year ago, when I started reading up on mead making, I read that the ancient Greeks and even the Mayans, who lived in hot, humid Central America made mead and, last night, as I pondered on your and Fatbloke's comments, I thought of these ancient mead making cultures and wondered how they, especially, the Mayans, handled large amounts of mead making without any cooling systems. They must have made small batches at a time.

The Ethiopians make their own type of mead in Africa. Gets pretty hot there, too. ;D

Of course, I also thought that the Greeks and Mayans didn't have 130 gallon tanks although I've seen ancient Cretan urns that seem pretty big.
I intend on making a small business out of mead making. The tank I have is an experiment to produce approx 200 bottles of mead which, if profitably sold, will indicate to me that more tanks of the same capacity can be bought to create a small meadery.

I have all the paperwork regarding the federal and local government requirements ready to be filled out but I am waiting for most important part of mead making: the honey source before starting the paperwork. I found two here on the island. One has a 55 barrel of honey for $1,000 and the other for $1,200. The $1,200 barrel company will deliver it, raise it to your tank and pour it in the tank.

I had to buy the tank from Germany because I couldn't find a stateside fermentation tank that would ship outside the continental U.S. The same with 750 ml wine bottles. If you guys know of any wine bottles companies that ship outside the continental US, please let me know.

I am going to seal my bottles the old fashion way with cork and bee's wax with a bee imprint on the still soft wax. I have the bees wax ready. I already designed the label which will be clear/see thru. I want to buy a case of wine bottles to experiment with the wax and labels.

Anyhoo, this is going to be a trip which I intend on enjoying.

Again, thanks.

Medsen Fey
09-27-2010, 09:26 AM
Another issue to contend with is storage of your bottles. If you keep mead stored at 100F (like in the garage here at the Fusel Shack), you're meads may take on a "cooked" character with an aroma/flavor of Sherry or Madeira wine. If that is what you are aiming for, then it is fine, otherwise you may have a lot of disappointing bottles.


P.S. Welcome to GotMead!

P.P.S. You should enter yourself on the GotMead member map.

09-27-2010, 08:32 PM
Greetings Medsen Fey. Thanks for the welcome. I will be checking out the GotMead member map soon as I dash in and out of the internet as I have time.

A sherry-like, sweet wine with exotic fragrance is what I want in my mead. I did a lot of internet research on spices as well as on some exotic honeys from around the world. I want to try using buckwheat honey sometime in the future and that rare honey made from the nectar of the flowers of the leather tree in New Zealand (Tasmania?) sounds really interesting for small batches because the price would be astronomical by the gallon. Some of the people who have tasted my Passion Fruit with cardamom mead say its an after dinner type although it packs a good punch. Sometimes, I will be sipping some in front of the PC and if I don't watch my swallowing, I'll break out coughing. Good stuff. I drink it in a large brandy snifter to enjoy the aroma but only two servings of about a fourth of a cup each. Like I said, it packs a good punch. Come Christmas and New Years, more than a fourth of cup, of course. I have about 5 gallons of experimental batches in a dark closet for Jolly Season to enjoy with friends and family. ;D

As long as the tank doesn't burst sending my investment down the drain, I think it will be alright. The other thing that worries me is contamination with bacteria or whatever when I give the tank its daily aeration with a long paddle. How long should I stir? Will 5 minutes of steady stirring be enough aeration?

The temperature here is usually upper eighties thru lower nineties. I'll turn on the air conditioner if it hits 100+ which won't be until next summer since it's starting to "cool" into the lower nineties now that's it fall. :cool: Winter is usually in the 80s although in wee morning hour it can fall into a upper sixties on the coast where I live and lower 60s in the mountains. It can hail but it never snows. Endless summer here.

Is mead supposed to be drunk cold or room temp? I like it room temp but cold is fine with me.

It's a friendly forum. Helpful people. Feels good. Thanks.


Chevette Girl
09-27-2010, 11:32 PM
Is mead supposed to be drunk cold or room temp? I like it room temp but cold is fine with me.

Welcome aboard! I hope your meadery idea works out! Sounds like you've thought about everything!

As for how mead should be enjoyed, it's a personal choice... I like cool/cold beer but I prefer my wines and meads to be room temerature, or at least no cooler than basement-chilled (yes, whites too, I find cold wine has no taste). And other people will probably enjoy chilled mead.

09-28-2010, 12:38 AM
Incidental contamination from the air is not a huge concern during primary fermentation. Open-topped fermenters are still used today (yes, that means absolutely no lid). Sanitize your stirring equipment and you should be fine.

I have no experience for such large containers, so I have no idea if 5 minutes of aeration will be sufficient. Typically the mead is stirred & aerated during the first third of the fermentation, and definitely not after the halfway point. Some stirring (without aeration) can help keep the yeast going during the last half of fermentation, but with such a high temperature you might not need it.

09-28-2010, 08:25 PM
Hi Chevette Girl. Thanks for the welcome. Great forum.

Seems I've covered the main concerns on my mind regarding the fermentation of mead.

I've sent more emails to more wine bottle companies in my search for clear 750 ml Bordeaux style wine bottles that can be shipped to Alpha Centauri Penal Colony No. 313-D ;D . What a trip.

Ok, guys, thanks. Later.

Beam me up, Scotty. Warp trillion, Mr. Chekov.