What do you want from an experiment?

Please, I beg that the few of you reading this post a comment so I can make up my own mind. (Who could be expected to do that on their own?!)

The next experiment I'd like to do is to test pitching rates on a standard gravity (23*Bx, SG 1.097) mead; a duplication of an experiment from a scientific journal. My problem? What would you care about: many gravity and pH readings to see how the different pitching rates effect kinetics (ie. high sample rate of 4-8 hrs between samples), or modest sample rate (~12hrs between samples)? Obviously the former is better, however, I work; I'm a real person! (Sometimes?)
Basically, if people are OK with a low sample rate (inconclusive fermentation kinetics data), then I can start soon; if people would prefer accurate kinetics data I would have to wait for several weeks, possibly months. It's your choice, wait (even longer), or deal with only moderate understanding of how pitching rate effects fermentation kinetics.

If no one feels like commenting, then don't complain! (Not that you'll post your complaints, but I'll still here you!!!)

Yeast Rehydration

Why?

Choosing a yeast strain is vital to the final quality of mead (and beer, wine, sake, even spirits), as is the care that is taken to nurture them. For the purposes of mead (and wine, because we are mostly using wine yeast strains), we will most often encounter dried yeast as they are more numerous in selection, cheaper, and there is no damage caused by the drying process (beer yeast, especially lager yeast, are rather difficult to cultivate in a medium that permits drying, and can often have mutations result from the process; though techniques have improved drastically over the last few decades). The funny thing about the drying process is that it is not all that harmful to yeast, but the 'waking' is turbulent and rather tiresome for our little helpers. We are basically starting from very weak little creature who are just waking up and we want them to run a marathon; granted it's in their genetics, but without proper conditioning they may pass out at 26 miles instead of the 26.3 they were supposed to run. 

They yeast companies have done a good job feeding the yeast many things that they will need to actually get out of dormancy (high oxygen, nutrient dense, and low osmotic pressure media give them the reserves they need for the trauma about to occur), but once awake, they have to deal with their environment which can be rather harsh (lack of nutrients, and relatively high osmotic pressure), and they may give up. The number of yeast cells that die upon 'sprinkling' (the common technique of just opening the pack and adding the yeast to the must/wort) ranges a considerable gamut with some sources saying as low as 20%, and some claiming almost 2/3! I tend to think the mode number of 50% is most accurate, but even if it were only 20%, that's a lot of helpers you are killing off. The cells that do survive and work are not in very good shape either: having depleted their energy reserves (glycogen and trehalose usually) they have to spend a considerable amount of time and further energy to rebuild these levels in order to get to the point where they can actually start working.

In an environment like mead, where there is always a shortage of yeast assimilable nitrogen, lack of micronutrients, low pH buffering capacity, high osmotic pressure (usually very high compared to other fermentations), why would we want to use yeast that were even the slightest bit unhealthy? Why risk a stuck, stinky, or non existent ferment? "That's never happened to me and I don't rehydrate.", me either, but at least I've got money on the high half, first third and a zero while your all on 31! (sorry, roulette/james bond reference)

Pitching Rates

A quick note on pitching rates is in order here. Pitching rate is measured as CFU/mL (colony forming units per milliliter), but can be approximated using g dried yeast / L of must; assuming 20,000,000,000 (2*10^10)CFU/g dried yeast, we can estimate the resulting pitching rate of X grams of dried yeast added to a liquid whose total volume is Y. Great, how much do I pitch? 0.005-0.5g/L is a good range, that's 10^5-10^7 CFU/mL. More specific? Almost all manufacturers recommend 0.25g/L (~1g/gal), winemaking textbooks say 0.1-1% by volume (which is ~10^5-10^6 CFU/mL), researches have found that 0.5g/L works best for high brix musts, and brewers pitch anywhere between 6*10^6 - 2*10^7 CFU/mL! The best 'rule' to follow is

<24*Bx (SG 1.101) gets either 0.25g/L or 1g/gal, whichever measurement you prefer; 

25-28*Bx (SG 1.106-1.120) gets 0.3g/L or 1.2g/gal

>28*Bx (SG 1.120+) gets 0.5g/L or 2g/gal. 

That is not to say that many people don't cross these boundaries and make unsatisfactory meads, many people do for many reasons, it's just a guideline. Also, there has been research that suggests lower pitching rates enhance the flavors of mead, but I would stick to these guidelines for now (sometime soon I will be starting a pitching rate experiment focusing on the lower end of the spectrum). 

Basic Procedure

1g yeast strain of choice

1.25g Go-Ferm Protect (or what ever their (lallemand's) newest one is, I think evolution)

25g water

          -multiply all numbers by your chosen amount of yeast (pitching rate * volume)

• Boil the water for a few minutes (pasteurization), I would recommend boiling more than needed and weighing afterwards
• Put into a thoroughly sanitized flask (Erlenmeyers work the best), if you can autoclave it (truly sterile), I would
• Wait until the temp is down to ~110F
• Add Go-Ferm 'whatever' and swirl (this is why erlenmeyers are best)
• Wait for the temp to drop to 104F
• Add yeast, swirl gently to break-up clumps
• Wait 15-30min, don't exceed 30min or the yeast will start to starve

Notes

There are actually a range of temperatures that work best for rehydration, from 95-105F, and it depends on the specific yeast strain, but most seem to prefer the upper range with a mode of around 104-105F (40C).

You'll note that the amount of water is by weight not volume, why? 50mL of water at 110F weighs less than 50mL of water at 40F (about 454mg less); if you measured the volume after boiling (while hot) you won't use enough water, and if you measure before boiling you wont be able to account for evaporation. Therefore, weight is the way to go for precision. 

As to the type of water, clean, potable water with no chlorine or chloramines is recommended. The Go-Ferm will not replace minerals found in water, therefore, the water must have a certain amount present for healthy rehydration. The hardness is a vital factor for yeast health with best results being achieved between 250-500ppm hardness.

This entire process is basically proofing the yeast and allowing their cell membranes to form properly, it does not acclimate them to the must, nor add any special property to they yeast, however, it does not damage the yeast as would happen by the 'sprinkling' method. 

Add-Ons

These are extra steps that can/should be added to the basic procedure when the circumstances dictate.

Temperature

The best 'add-on' is an acclimation phase for temperature. Simply put, take your slurry and add some must to it so that the yeast aren't shocked too much by the temperature. More technical you say? For every 18F (10C) difference between your must and starter, add an amount of must equal to the original starter size to the flask.

So, I have 6gal of mead must and want to pitch 8g D47.

I rehydrated with 10g Go-Ferm in 200g of water. I now have a starter/slurry of about 200mL (give or take), that is at 84F, and my must is at 66F. 

I need to take 200mL of must and slowly add it (over a few minutes) to my slurry and wait 15-30min.

If the slurry was at 92F and my must at 56F, I would need to make 2 x 200mL additions to my starter. 

This process works to slowly acclimate the yeast to the temperature, gravity and pH of the must. Because it works for gravity and pH also, it is usually recommended to do this even if the temperature is within the 18F tolerance.

Very High Bix Musts

For very high brix musts (>35*Bx, SG 1.154), there are more delicate steps that should be taken to avoid osmotic shock that can happen even if utilizing the routine above. The method I describe here was put forth by Kantkanen et al. fot the production of ice wines. They tested several procedures across 2 pitching rates (4*10^6 and 10^7 CFU/mL): acclimated rehydration vs simple rehydration, and utilization of Go-Ferm vs none in the rehydration step. The starting gravity of the must was 37*Bx (SG 1.164), and the results showed that only those fermentation pitched at 0.5g/L (10^7 CFU/mL) were able to reach 10%abv, and that utilizing the following process with a lower pitching rate did not achieve desirable results; starters that underwent acclimation showed an increase in consumed sugar compared to non acclimated starters. 

Interestingly, while the use of Go-Ferm decreased fermentation time and acetic acid production, it also decreased the amount of ethanol produced as a function of sugar consumed (ie. sugar was consumed quicker than the non Go-Ferm batches, but it's utilization for ethanol production was relatively lower).

Here's what you do using a 25mL slurry as made above (just multiply the volumes for larger amounts)

• Take sample of must and dilute with sanitized water to 20*Bx (SG 1.083)
• After initial 15-30min wait (above), add 25mL of dilute must to starter (the result should be a 50mL starter at 10*Bx)
• Place flask in water bath at 77F (25C), for 1hr swirled every 30min
• Take a second must sample and dilute it with sanitized water to 30*Bx (SG 1.129)
• After 1hr wait add 50mL of the second dilute must sample; resulting in a 100mL starter at 20*Bx
• Place flask in water bath at 68F (20C) for 2hrs, swirl every 30min

Be warned, this works really well and creates super tolerant yeast that can pass their alcohol tolerance by a few percentage points (actual abv accounting for shift in composite density). Technically this process results in a solution that is equal to 

                                                       25g dried yeast / L of water,

meaning that you would need to pitch 20mL starter / L of must to equal the 10^7 CFU/mL (0.5g/L dried yeast) recommended.

If you want to ferment something higher than 40*Bx (SG 1.179), I would high suggest step-feeding (adding honey in multiple increments during fermentation). However, if trying a polish style mead, or some other absurdly high gravity style, and you do not want to step-feed, I might suggest trying this method with an additional step of adding another equal amount (100mL in our example) of must to the starter for ~3hrs with swirling at 30min intervals (or stirplate the whole time!). Note that each addition has made a 10*Bx jump; in keeping with this the gravity of several additions can be estimated:

20*Bx addition to make 10*Bx starter

30*Bx addition to make 20*Bx starter

40*Bx addition to make 30*Bx starter

50*Bx addition to make 40*Bx starter

60*Bx addition to make 50*Bx starter

Obviously I did not have to list those as they are in 10*Bx increments with a 10*Bx offset, but I did want to show that at 50*Bx and above, it is almost useless in trying to ferment without some sort of gradual addition of fermentable material during the process. 

Experiment: Boil v. No Boil (Part 2)

pH as a function of time (hrs). Nutrients added at
roughly 24, and 82hrs.

It's data and conclusion time! (or partial conclusions)

Boil
OG: 1.1080 --> FG: 1.0025
pH 5.60 --> pH 3.56

No Boil
OG: 1.1080 --> FG: 1.0015
pH 5.33 --> pH 3.56

Both fermentations were held within 1C of 20C (both had peaks of 21C @ 92hrs from pitch, right around the pH stabilizing). Nutrient additions and aeration were determined by gravity reading, not time after pitch.

Specific gravity as a function of time. Nutrients
added at roughly 24, and 82hrs; aerated at
roughly 24, 44, 58, 68, and 82hrs.

Unfortunately, the data points were not as close as I would have liked, but life gets in the way of things.

Nutrients were added at roughly 24 and 82 hours after pitch, showing a slight change in slope in the gravity graph, and a 'bump' in the pH graph (the other 'bump' in the pH graph at ~44hrs seems to correlate to aeration).

It is clear that the yeast are active well before a drop in gravity, this is shown by the drop in pH before ~24hrs (when a drop in gravity was first detected). This corresponds to the acclimation period which yeast go through commonly called the 'lag phase'; it would seem that instead of active sugar metabolism, they are more concerned with making an adequate environment for themselves at this point.

As to the differences, it would seem that the boiled must had a higher pH throughout the process until the end of fermentation. This is contrary to common belief that boiling (and skimming) reduces the buffering capacity of mead musts, however, this may be an outlier as the honeys chosen for the must composition do naturally have higher mineral and ash contents than other honeys (avocado and lychee are particularly rich in both, the brazilian pepper had a very high pollen content, and the beach plants have a higher mineral concentration than average (White Jr)).
Also the boiled mead fermented a little faster (about 2 days, though the data is not accurate to the hour, hence it's non-inclusion in the graphs).

Both have been cold crashed for 2 weeks at 5C, and have been treated with sulfites (an addition of 1 campden (Kmeta) was added to each gallon container, this method was chosen for its prevalence throughout the mead and winemaking community). They will age for another 9mos before being racked and bottled. Bottle aging will be in 12oz beer bottles with O2 absorbing caps, and evaluation will be held at several points in their lifetimes (hopefully ~1yr, 2yr, and 3yr, but we'll see).

I'm going to start tweeting links to new posts; that way, instead of nobody checking to see if I have a new post up, no one can follow me on twitter to see if I have a new post up!  @BOB_1and_only is my twitter thing (I think it's a "handle"). If I sound like the robot from the hitchhikers guide than it's working; not that anyone cares. ;)

Mead: Etymology Part 1

I have a fascination with linguistics, particularly etymology. So instead of the standard "here is how to say mead in 20+ languages", I'd like to take you on a journey through the Indo-European language family via a single word: *med^hu.
First a quick note on some linguistic things. The * means that the word is reconstructed, meaning "we don't really know, but this is a very, very, very good guess that a few dozen people, with a few dozen letters following each of their names, have come up with using historical linguistic techniques (like comparative analysis, and internal reconstruction)". A proto language" is a hypothesized language that would account for similarities between several other languages; strictly speaking it is the youngest language that contains traits of several members of a language family or subfamily.
Proto-Indo-Eutopean (PIE) is the hypothetical language that led to all Indo-European languages; it was probably highly inflected, and would have had a considerable number of crossover words that could have meant the same (or similar) thing(s). Over time, PIE broke apart (probably into dialects which would later represent individual proto languages) and formed different branches of the Indo-European language family, which in turn broke into further classifications or became extinct.

This diagram represents the Centum languages in the Indo European language family; what one might consider the "european" groups. The gray/grey areas are proto-languages for which we have reconstructed words. The yellow/gold indicate languages for which the word listed means mead (or honeyed, sweet, alcoholic drink). Note that the Mycenaean language is in teal due to the fact that the liner B script used to write their language was borrowed (probably from the minoans) and does not fully account for the sounds of their language (ma-tu-wo could have been spoken as matuw, matwo, matuwo, or any number of variations). 

*méd^hu vs *mélid 

All three of these words could have been used to describe what one harvested from a beehive (honey).

*mélid  survived to specifically mean honey in many branches of the language family (greek, celtic languages,  italic languages, anatolian languages, and even germanic languages usually evolving into the word mildew (I have no f**king clue why!)). 

Mead/Wine/Drunk(eness/ard)

It is interesting to see that the etymological root word *méd^hu came to mean a number of things. In it's original form from PIE, it may have meant any drink made with, or having a honey-like flavor, but also could have specifically meant mead (I could describe sauternes as *méd^hu, but I would not call it that as it's name (adjective vs noun sort of idea)).

In hellenic languages it came to mean wine by the time of Old Ionic, and by modern it means drunkenness, and stands in ablaut relation to the word that means drunkard. It also stands as the root for the words that come to mean methanol, methylene, methyl, and methane.

Of very interesting note is the complete disappearance of this word from the italic languages, only for them to re-invent a word for it. I could list theories and cite shady evidence, but it does no good to do so. It is more interesting to see the word that the italic languages use for mead: 'water' + 'honey'. Note that I do not say 'water-honey' as a single idea, if that were the case Spanish, French, Portuguese and Catalan would all have similar phonology (sounds), instead of the obvious translation of 'water' + 'honey'. 

The Germanic and Celtic languages preserve this word and the meaning almost in its entirety. Mjothr, mid, mead, met, meede and medd all descend (rather obviously) form the same historical root, *méd^hu, and all preserve the meaning of fermented honey, regardless of how rare the term is, or how niche the word in their respective cultures (with the older ones probably retaining it's use more than the surviving ones).

Mead making rules

Here are some rules for the hobby of mead making. They're in no particular order, and don't take precedence over one another, with the exception of rules 1, 2, and 10 (with 10 being the most important).

1. You must talk about mead making. 
It is vital to spread the word about the hobby, and educate others about mead: the culture, art, taste, versatility, and general awesomeness. It is also very important to recruit other mead makers, not only to grow the hobby, but for your own education; by teaching others, we can learn more than by working in seclusion. A student can have a unique perspective that can induce our own creativity and break us from the binds of dogmatism.

2. You must talk about mead making! 
Just do it. Go to your homebrew club, join GotMead, or other forums. Go . . .  do!

3. Thoroughly clean and sanitize everything. 
Keep in mind that sanitizing is different than sterilizing; the goal of sanitizing is to reduce the cell concentration (CFU/mL) of potentially harmful microorganisms, not rid them entirely. There is a balancing act involved in this: if you don't pasteurize your must (boiling or lower temps), you have more CFU/mL than a must that was sanitized, and may want to be more diligent in your sanitation practices pre fermentation (longer contact times with sanitizer etc). Never think that your equipment is sterile, it's not, just think in terms of concentration of cells and you'll make the better judgements. Also, make sure everything is cleaned before sanitizing (and that the detergents used for cleaning are thoroughly rinsed or neutralized).

4. Patience is more than a virtue, it's a requirement! 
There are several ways to make a mead that is drinkable early in its life, but almost all mead benefits from some aging time. This is easy if you have a few cases in stock that are ready to drink, but to those who don't have that, utilize those quick mead recipes to quench your thirst while you wait for your other batches to age (or brew some beer, comparatively, it's much faster to drink). If you don't have patience mead making will teach it to you!

5. Mead making is not brewing, nor is it entirely wine making. 
There are principles that can be applied from both disciplines, but mead making is unique and breaks certain rules of brewing and winemaking.

6. Get in there, and be involved! 
Sensory analysis, that's what this rule is about. Taste and smell as often as possible: during fermentation, when your aerating, smell it; when you pull gravity samples, smell and taste; when you rack, smell and taste; during aging, every few months, smell and taste; when bottling, smell and taste; set some bottles aside (12oz work great) and preform a thorough tasting at 6, 12, 18, 24 months and longer.

7. Be creative. 
Try new things, and see how they work. Make a to-brew list, but be warned that you will never work your way through it (and if you do, you aren't being creative enough).
8. Avail yourself of local resources.
This is a hard one for me as I love berries and they don't grow well here in south florida; even though I have access to hundreds of varieties of mangos, and rare fruits that most have never heard of, I would love to have access to truly fresh blackberries and raspberries. Take advantage of unique honey varietals (avocado, saw palm, Brazilian pepper, mangrove, and mango in my case), that are local, or unique fruits (or herbs) that are grown in your region.

9. It's your mead, make what you like! 
If you like your mead to be full of mercaptan thiols and disulfides, who am I to argue. I won't have a glass, but it's not my mead. Once you have tasted other meads (via rules 1 and 2), you'll begin to understand what you like in a mead, and if it's something that others don't like, oh well; but do not think that your mead is the pinnacle of mead making if you have such strange tastes, be aware that others may not like what you do.

10. Have fun! 
Find what you enjoy most about the hobby, and guide yourself to doing that the most. If you really like experimenting, experiment; if it's the process of fermentation, get in there and enjoy it; if it's tasting, utilize rule 6 a lot. Just have fun and enjoy the hobby.

Some Brix Curves

 Here. . . have some brix curves. The ones to the right show three different musts fermented with the same yeast. I can't draw very much from these because they are single data sets; I wish I had them in triplicate to see if there are any trends, but I don't. Also note that I don't have data for the final parts of fermentation (<6*Bx), but they all slow compared to the main part, without dragging on for ever.

Below we have 5 ferments, 2 palm, 2 orange blossom, and 1 brazilian pepper (AKA Christmasberry). The original plan was to have 2 of each kind of honey, one with a control yeast (D21 here), and the other a different yeast, but life gets in the way, and I needed some honey for a bochet in a pinch (the brazilian pepper worked nicely).

All 5 have the exact same recipe except for the honeys and yeasts: same additives, nutrient schedule, fermentation temps, pitching rates, gravity (original and final), etc.. They are all getting some sur lie treatment right now and should be coming into their own by next winter.

These aren't perfect data sets, and can't tell much, but they do show the general shape of a healthy ferment. Some have faster drops, others slower, some have longer lag phases, and some finish fast and others slow (though none were too prolonged).

The recipe can be found on this GotMead thread, but it does require Patron status on GotMead (which any serious meadmaker should have anyways!).