carboy-airlockIn the world of mead making, especially amongst those who are new to the craft, there seems to be an abundance of mystery, uncertainty, and just general nonsense surrounding the concepts of a secondary ferment or fermenter.  Already you may be wondering what the difference is.  My goal is to clearly define what we’re really referring to with these terms, and what really happens “…in secondary.”

First of all, we have to get some terminology clear.  We often hear people referring to “racking to secondary” or even to “tertiary.”  Quadrutionary, anyone?  But we don’t often distinguish between a secondary fermentation phase and a secondary fermentation vessel.

  • A secondary fermentation phase, is a second phase of fermentation that occurs after the primary fermentation phase.  It might be planned or unplanned, but it has little actually to do with the vessel the mead is in at the time.
  • A secondary fermenter, or “racking to secondary,” is quite simply a misnomer.  Referring to a container, vessel, carboy, bucket, or otherwise as a secondary fermenter opens up a world of opportunity for misunderstandings.  The action of transferring our mead into another vessel, to accomplish a specific purpose, is really what we’re talking about.


To get to what a secondary fermentation phase really is, let me first describe the primary fermentation phase.  At its most basic, a mead begins with the mixing of water, honey and yeast, at which begins a period referred to as the “lag phase.”  Arguably, during this period, no actual fermentation is taking place, because the yeast are busy absorbing oxygen, uptaking nutrients, and getting their little yeasty freak on, reproducing like crazy.  Once they’ve done all that they get down to work, and the anaerobic process of actual fermentation takes place.  The yeast eat sugars, and produce alcohol and carbon dioxide.  This is called the primary fermentation phase, which is marked by all the sparkly bubbly activity, and the smells of heavenly wonderfulness coming out through the airlock, or whatever you have covering your fermentation vessel.  If you wish, you may refer to this as your “primary fermentation vessel,” or “primary fermenter.”  I’ll allow it.

If you’re a good and diligent mead maker, you’ll manage and monitor your primary ferment by doing many things frequently, including regular oxygenation and degassing, staggered feedings, staggered nutrient additions (SNAs), temperature control, and regular monitoring of pH and gravity.  In these ways, and more, you will ensure a healthy and complete primary ferment takes place.  By monitoring your gravity readings regularly, you will know when your primary ferment is nearing, or has reached, its end.

Here’s where we get into a little grey area, or at least some room for discussion.  Some consider the primary ferment to be the most vigorous phase of fermentation, which at some difficult-to-define point transitions into the secondary ferment.  Granted, at the tail end of the ferment there are some important things still happening that are not so obvious to the naked eye.  Yeast are cleaning things up after the party, disposing of the evidence before mom and dad get home, and getting ready to go to bed.  But I suggest that referring to this “trailing off” of the primary ferment phase as “the secondary ferment” is not only confusing, but inaccurate.  This is simply the end of the primary fermentation process.


Now it’s usually around this time that people start wondering about the timing and necessity to “rack,” or transfer, the mead out of the primary fermentation vessel and into another container.  The timing and necessity of this action depend entirely on what doing so will accomplish for you.  The conscientious mazer should consider this purpose thoroughly before following any formulaic arbitrary advice he or she may have read in some mead recipe posted online.  For example, if a recipe tells you to rack after 7 days, and every two weeks afterward until clear, you might want to rethink going with that recipe.  The author is not thinking clearly, and my suspicion would be that there are other logical flaws in the recipe as well.

Racking your mead from one vessel to another does a few things:

  1. It separates the liquid portion of your mead from any solid sedimentary particulates that have precipitated to the bottom of the vessel. In the particular instance of your first racking, this primarily consists of separating your mead from 90-95% of your yeast.  More on this later.
    1. If you’re doing a fruit mead, or you have other large chunks of stuff in there (spices, oak chips, etc.) this action also serves to separate the liquid mead from the solid chunks.
  2. It partially degasses your mead. Through the action of moving the liquid from one place to another through a small aperture, some carbon dioxide is released from solution.
  3. It necessarily sacrifices a small portion of your mead, which gets discarded with the solids/precipitates at the end (i.e., you lose a little of your precious liquid each time you rack).
  4. It creates an opportunity for careless transfer techniques to introduce oxygen into your mead. Post fermentation oxygenation causes your mead to smell and taste like sherry or cardboard, and is almost always considered a flaw by judges. The technical term for this is “bad.”
  5. It offers a slight possibility of infection. I say slight, because (1) I’m assuming good cleaning and sanitation habits, and (2) the higher the alcohol content, the more inherently resistant to infection.  Not saying you can get sloppy, or use that racking tube you just moved your sour ale with to rack your mead.  Just pointing out that at this point the mead has some degree of built-in defense.

As you can see, there is a lot that happens when you transfer.  Your job in deciding whether, and when, to transfer is to weigh the risk of doing so against the reward for doing so.

Does racking actually do anything to help your mead clear faster?  Yes and no.  If this simple action helped mead clear faster all the time, we would rack our mead a dozen times with every batch.  But remember that racking primarily serves to separate your mead from something, and ‘that something’ might be keeping your mead from finishing the way you want it to.  Racking your mead away from some types of sediment might actually improve your conditions in a way that will speed up clearing!

  • Example 1: Traditional mead.  Your primary ferment is complete, and you’ve racked your mead to a glass carboy to begin clearing.  After a month you come back to check its progress.  The mead is clearer, and there’s a pale creamy sediment on the bottom that looks like yeast.  You might be thinking it’s time to rack, and you might be right.  Is the presence of the yeast there doing any harm?  At this point, not really.  Some of the yeast have died, yes.  But most of the yeast is dormant due to the alcohol presence, and won’t actually start to die and go through the process of autolysis (where their little bodies break down and release yeast guts into the mead) for another couple of months.  So the question to ask yourself is: Is the risk of infection, oxygenation, and volume loss worth the reward of moving the mead off of the sediment at this time?  Personally, I would let this batch sit another month, because as I said, it’s clearer, but not completely clear.  I would degas this batch carefully, to avoid oxygenation, and give it another month.  You may choose differently, but just do so mindfully.[break]
  • Example 2: Continuing on the above example, you give the mead another month, and it is substantially clearer, but still not the brilliant crystalline goodness that you know you need. Chances are now all the yeast has fallen out, and you’re only dealing with some kind of faint, undefined haze.  Maybe you’re beginning to become concerned about autolysis.  Racking now will separate your mead from the sedimentary yeast and other goobers that have settled out already, and give you an opportunity to employ other clarifying methods, such as cold crashing, clarifying agents, or simply more time.  With a traditional mead, such as we’re assuming here, I would personally rack this and either bulk age or use a clarifying agent such as bentonite to clean up the haze.  Your preference may be different, that’s just how I roll.

Deciding the right time to transfer depends on a thoughtful analysis of where you are in your ferment, what you’re observing, and what you’re hoping to accomplish.  If your goal is to slow down or stop your primary ferment earlier than it would if you just let it go its natural course, then racking helps to separate your mead from the majority of the yeast biomass (which tends to hang out on the bottom anyway), which can slow and stop your mead early, resulting in a sweeter mead.  If your process involves fruit pulp, or oak chips, or some other flavoring agent, then the purpose of racking is to separate your mead from that ingredient.  The process and progress of the ferment dictate the timing, not the other way around.  With time and experience, and careful evaluation of what you want to accomplish, you will learn to “listen” to your mead, and let it tell you when to transfer.

Recap: There are many reasons and times at which a mazer will transfer his or her mead from one vessel to another.  The terms “secondary fermenter” or “racking to secondary” just don’t make any sense, and ought to be avoided.


Is there such thing as a “secondary ferment”?  You bet there is.  But it doesn’t just automatically happen when you transfer your mead out of the vessel where it underwent its primary fermentation phase.  Your mead can and will, for a variety of reasons, finish its primary fermentation phase and then at some point later in life enter into a secondary fermentation phase.  Why would this happen?  Sometimes a secondary fermentation is purposeful; other times it happens on its own, and the results can be apocalyptic.  I’ll list a few factors that can cause secondary fermentation:

  1. Temperature change. Yeast are very sensitive to temperature, and even a 5 or 10 degree increase in temperature can spur some additional activity.
  2. pH change. Your mead’s pH changes over time based on a variety of factors, even well after the primary fermentation phase is complete.  Release of carbon dioxide gas (degassing or off-gassing) removes carbonic acid and actually raises your pH.  Yeast have preferred pH ranges, and so even a slight change here can wake up dormant yeast into another period of activity.
  3. Infection. Bacterial infection can take place at any time from the moment you begin mixing honey with water, to bottling.  Not all infection is bad.  Inoculating your mead with yeast or bacterial cultures is simply an intentional infection. The aftermath of an unintentional infection, however, can show up later than you expect, and with devastating consequences (e.g., bottle bombs).
  4. Introduction of other ingredients. Additions of fruits, spices, other yeasts, intentional inoculation with bacterial strains for souring, blending of meads, addition of other fermentables, even oaking, all have the potential to change the conditions of the mead such that a secondary fermentation phase can begin.

Recap: A secondary fermentation phase has nothing to do with the vessel it is in at the time.  A secondary fermentation phase might very well happen in the primary fermentation vessel!  A secondary fermentation phase could also happen after blending, or after you bottle.  Bottle conditioning is a separate controlled ferment that happens inside the bottle, to create a sparkling mead.

Without getting too far into the weeds though, you can see that there are a variety of reasons a mead may go through a secondary fermentation phase, or even a tertiary.  If I’ve done my job here, you also see that racking your mead into another container doesn’t magically spark some kind of secondary fermentation phase all on its own unless you have some serious cleaning and sanitation problems.  Hopefully you now have a better understanding of what really happens when you transfer your mead, and the control it gives you as a mead maker.

I encourage your questions and comments to this article.  Please feel free to comment below, or reach out to me on the forum.


Jason Bishop
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