This is a blog post which accompanies my latest YouTube video, with both focusing on how to brew a wild mead using honey and yeast gathered locally. This post contains a lot of the finer details not discussed in the video, so if you are thinking of replicating this mead, I would suggest you first watch the video and then come back to this post. You can find the video at this link, and embedded below.
Yeast From Bees?
Many people may be surprised to learn that you can isolate yeast from bees. But that said, its long been appreciated that bees, along with most other insects, contain a large number of yeast in their guts. In fact, the bee microbiome is astoundingly simple…and attractive to the wild brewer. The bee microbiome can be divided into two major groups – yeast and bacteria. Among the yeast you will find brewers yeast (Saccharomyces cerevisiae) and some of its closely related cousins (e.g. Saccharomyces paradoxus), as well as some more interesting yeasts. One of the most interesting of these yeasts are the four or so species in the Lachancea genus. These yeast are unusual, in that they can ferment simple sugars such as glucose and maltose into lactic acid – meaning they can single-handedly make sour beers, ciders, meads and wines.
The second “half” of the bee microbiome are the bacteria. And bees only really have two kinds of bacteria kicking around in their guts. Acetobacter, which in the presence of oxygen can transform alcohol into acetic acid. This genus of yeast is used to make vinegar, as well as beverages such as kombucha. The other half of the bacterial microbiome is comprised of our good friends the Lactobacilli. These are the bacteria most often found in sour beers, and give them their characteristic sour punch.
Wild Mead from Bees?
On the surface it would seem like it should be easy to get beer/mead/cider/wine friendly wild yeast and bacteria from bees – just mush up a bee or two and toss them in the must. But there is a problem…make that two problems.
The first problem is that the diet of bees is very simple – honey & pollen. Yeast don’t care much about the pollen, but they do eat the honey. And honey is simple sugars – mostly a 50:50 mix of glucose and frutose, with small amounts of sucrose and other simple sugars kicking around. And this is the cause of our first problem: many of the yeast in bees have evolved to only eat simple sugars, but cannot eat the more complex sugars found in something like beer wort.
The second problem is that the bee intestinal tract doesn’t have much alcohol in it. Meaning that many of the yeasts living in a bee lack tolerance to alcohol concentrations over 1% or 2% ABV. In other words, many of these yeasts – even if given an appropriate mix of sugars – would only ferment a little bit before killing themselves off with alcohol poisoning.
Finding the Good Yeast
Given the issues I’ve outlined above, there clearly is a need to “proof” our yeasts prior to trying to ferment something with them. I show this quickly in the video (timestamp 1:50 to 3:20), but it is worth discussing it in more detail.
To get useful yeast, you need to setup an environment which mimics the extremes of a fermentation, and which mimics the nutritional environment of the beverage you plan on fermenting. I’ve found it simplest to divide these into two separate steps, which seems to give a better success rate than does a combined process. I generally select for alcohol tolerance first, and then for “nutritional comparability” if necessary.
Selecting for alcohol tolerance:
Choose an alcohol concentration that you consider to be the extreme of what you would use the yeast for. For example, in the video I selected 10% ABV for this concentration, as this is a typical ABV for meads. But this number can be adjusted lower (e.g. for beers & ciders) or higher (e.g. for stronger meads & wines). I would generally recommend you pick a value 1% to 2% ABV above what you plan on using, just to make sure your yeast can handle it.
Once you’ve selected your desired final ABV, prepare a standard beer starter of ~250 ml (1 cup) in volume, with a gravity of ~1.045 (e.g. 35 g of dry malt extract into 250 ml of water). Boil this to sanitize. Assuming your wild yeast have normal (for wild yeast) attenuation, when fermented this starter will have a final alcohol content of ~5%…which is not high enough for our purposes. To provide a higher alcohol content, add an unflavoured spirit to the boiled and cooled starter. You want to avoid flavoured spirits (gin, any of the sweet or herbal things), and ideally want a white spirit (vodka, white rum, white tequila, etc) in the 40-50% ABV range. Add enough of the alcohol to bring your starter up to the desired final alcohol content – e.g. if you want a 10% ABV final content, add enough alcohol so your starter has 5% ABV before adding the yeast, with the final 5% provided by the yeast’s fermentation.
To calculate the approximate amount of alcohol required, use the formula: Volume of spirit to add = (Starter Volume * Desired Starting ABV)/ABV of your spirit.
E.G. for a starting ABV of 6%, in a 350 ml starter, using a 50% ABV vodka: (350 * 6)/50 = 2100/50 = 42 ml of vodka, or ~1.4 fl. oz.
Once the starter is prepared, remove the abdomens of you bees (or wasps, fruit flies, or any other bug that likes to feed on fruits or flowers) and toss them in the wort. Oxygenate well, and let them ferment. Because of the added alcohol it is hard to use gravity readings to monitor the success of this step. But if you end up with a good thick layer of yeast at the end of a few days, it is likely that you were successful. If you have minimal growth after 7 days, consider this step a failure and try again.
Selecting for nutrition:
This step is optional, but keep in mind that a DME-based starter is nutritionally rich, and as such a yeast grown in this kind of starter may struggle in the lower-nutrient environments of cider, mead or wine. To select for yeast which can handle a lower-nutrient environment, prepare a starter where ~10% of the sugar content comes from DME, and the remainder from table sugar or corn sugar. I generally aim for a starting gravity around 1.045, and don’t bother with adding additional alcohol. Grow the yeast in this starter – anything which grows should be a strain of yeast which will perform well in a mead, wine or cider.
Staged Nutrient Addition and Degasssing
Those of you who’ve made mead in the past may recognize my approach to fermentation as a modified form of the TONSA method. This is not my invention, and so I’d direct you to the above link for a description of how to make mead using the TONSA method and its history. In brief, this is a method which uses staged yeast nutrient additions to allow for the rapid produciton of mead – in my experience, meads which take >12 months to prepare with traditional methods are done in 6 weeks using TONSA. I modified this approach in this recipe, mostly because of the small volume of mead I prepared. To perform TONSA correctly you need to take frequent gravity readings – the small size of my test recipes precluded anything more than a gravity reading before pitching yeast, and after fermentation was complete. As such, I condensed the three nutrient feedings into two – the first at the time of the yeast pitch, and the second+third added at the 48 hour time point.
I also used degassing, which is a method used in the brewing of high-gravity beers and also by some wine makers. Degassing can be an important part of maximizing the performance of your yeast, especially as you approach the limit of their alcohol tolerance. Yeast are highly stressed under these conditions – the alcohol is hard for them to tolerate, and in addition, dissolved CO2 acts to both acidify the beer/mead/cider/wine and this CO2 also limits the rate that some of the fermentation enzymes can operate at. We want the alcohol, so there is no way to reduce that stress, but by degassing the mead/beer/cider/wine we can reduce the CO2 stress. This can help ensure a complete fermentation, reduces off-flavours, and can speed finishing. I recommend degassing only during primary fermentation, as degassing after this point can introduce unwanted oxygen. I prefer to do this daily during primary fermentation, although the first two to three days are most critical.
To degas I take one of two approaches. For my mini fermenters I simply replace the airlock with a cap and shake, frequently loosening the cap to “burp” out the CO2. Once I no longer get a “burp” I know I’ve pushed the CO2 out of solution, at which point I put the airlock back on. Its not possible to seal & shake larger ferments, so for these I use a wine whip designed to go on the end of my drill. Sanitize the whip, and immerse it right to the bottom of the fermenter. Pulse your drill (maximum speed, 3-5 seconds) to knock CO2 out of solution – you do not want to stir to the point you get a whirlpool, as this can introduce oxygen. Keep pulsing until you get to the point where additional pulses don’t release additional CO2. If using a carboy, make sure to start slow. Pulse too vigorously, or for too long, and the neck of your carboy will act as a rocket nozzle that will spew a foamy, yeast-filled mess onto the ceiling, your head, and all over your tools.
One characteristic that separates meads from beer and wine, is that mead can be served still or carbonated. It is amazing how different the same mead presents itself when carbonated versus when still – carbonated, they are often lighter and with a more pronounced aroma and flavour. Still, they are softer and the flavours more complex. As you may guess, I almost always split my batches of mead, bottling a third or so carbonated, and the remainder still.
Packaging in this fashion does not need to be complex – transfer the mead to bottles as you normally would, and then dose honey into the bottles you wish to carbonate (obviously using appropriate bottles). There are a number of carbonation calculators out there which will tell you how much honey you need to add to carbonate, although a good rule of thumb is to add ~3 ml of honey per standard beer bottle (350 ml/12 oz). This will provide ~ 3.5 volumes of carbonation; safe for a standard beer bottle, but enough to be on-style for many kinds of meads.
Unlike wild beers, you can bottle wild meads pretty quickly after fermentation has completed. This is safe, as honey is comprised almost entirely of simple sugars, meaning there is nothing left for wild yeast (and other bugs) to eat once fermentation is complete. Thus, unlike wild beer, bottle bombs are not a concern…so long as you are dosing your carbonation addition properly.
Making a wild mead is an easy entry point into wild fermentations. The simple sugars of the mead must are fermented by a broader range of yeasts than are the more complex sugars of a beer wort. In addition, using the TONSA method can produce a drinkable mead in as little as a month, meaning you can enjoy the products of your wild endeavours much earlier than with wild beers, ciders or wine. As an added bonus, keeping bees is a fun and easy hobby, and one which can actually earn you a bit of money.