Yeast Making

[JohnD]

Perhaps this term is used in different contexts. I believe I have read papers referring to it in relation to recycling yeast and lactic bacteria back into the next mash. Certainly nothing would survive boiling.

[Denver Distiller]

There are, however, some historical accounts that suggest the term once had a slightly different meaning that may be related to the use of stillage not just in setting the fermenters but also in the yeast mash. Maker's Mark, for example, uses stillage in both.

We don't have tours often, but when we do, I always explain that sour mash is a poor man's way of acidifying the mash. You've got a nice, cheap (read: free) source of a liquid that's low in pH, and it can drop the mash pH to acceptable levels by using that sterile stillage.

What's also nice, and the reason that you use it in prepping yeast, is that stillage still contains yeast, or more specifically, all the minerals, nutrients, etc. that were consumed by the yeast during fermentation. What was inside the yeast when it was living, is now floating in the stillage after the boil. It's all right there, ready for the new yeast to consume.

So really, it's a combination of cheap acid and free yeast food. Pretty neat, actually.

JohnD, the lactic acid that was produced by any lactobacillus strains that worked in the fermenters will be present in the stillage, but, obviously, the bacteria itself will be deader than dead. So yes, you'll be recycling both yeast and lactic acid, but they won't be alive.

[delaware_phoenix]

The term I've seen used for taking yeast from the fermenter and adding it to the next ferment is yeasting back.

I know Chuck has talked about small distillers not using sour mash. It might be more accurate to say advertising, as in putting it on the label. When one week you make rye whiskey and the next something else, it's difficult to maintain the backset in a hygienic form without refrigeration or chilling. Even though the pH is low, given enough time and the right temperatures some kind of blue mold will start growing in it. Maybe it's penicillin and I should be really happy, but so far I haven't been brave enough to consider using it. The pigs like it.

[JohnD]

Thanks for the clarification Denver, I'm mixing my terms. I know there are acids in the spent mash, we look at butyric as a sign on microbial contamination as yeast won't make it. I guess I was wondering whether the practice of putting fully fermented, but not distilled mash, back into the next batch at the beginning of the next fermentation, might be about maintaining a specific lactic bacteria as you would with yeast. I think lactobacillus really only produces lactic acid but don't know that for sure.

I'll take a look around and see if I can find some lit. on that.

[Denver Distiller]

That's not really necessary (holding back ferment that's gone to terminal in the hopes of culturing lactobacillus). The easy and traditional way is simply to use wooden fermenters.... lots of carryover there. Open fermenters and no wort boiling will leave the fermentation ready for lactobacillus to do their thing. Malt brings in lactobacillus like cowboys riding on a bull.

You need to have your p's and q's together if you're going to encourage buggies.

[JohnD]

Haha it's certainly risky biz intentionally bringing other fellows to the party. I looked at a couple of papers on the subject. In one they tested Scotch distillery environments and found that the lactic population was as stable as the yeast population in the air and on walls and vents, but that unlike yeast (of which the population was limited to one or two) the lactic populations were as many as 5 organisms that were stable over a period of weeks. Variation occurred when grain sources changed a brought in new organisms.

In the presence of lactic acid distillation catalyzes the production of ethyl lactate (fruit/butterscotch) but any lactic bug will make enough for that and probably the most important factor is time in the fermentor.

Hope we haven't strayed too far from your original topic Chuck.

[Sherman]

Not unsubstantiated and not a wild claim.

The Encyclopedia Britannica: a dictionary of arts, sciences ..., Volume 15

By Hugh Chisholm page 742

At least one documented claim the same as mine from 1910. I clearly didn't make it up.

[Denver Distiller]

I don't understand. Do you think that certain varieties of lactobacillus that produce positive whiskey congeners can only be found in KY, TN, and PA?

[Sherman]

I don't understand. Do you think that certain varieties of lactobacillus that produce positive whiskey congeners can only be found in KY, TN, and PA?

I don't look at it in that perspective. I look at it as San Fransisco Sourdough.

The profile is suited for Bourbon and it is just widely accepted as THE flavor of Bourbon. The best experts in the industry are still blending and matching standards from the 19th century that were developed before the scientific methods. But the scientific methods have been used to purify and augment the production, purity, and consistency.

When you are fermenting in 35 foot deep 80000 gallon fermenters, one contaminated batch is very costly. Risk reduction is the way.

On the conversation about using backset, there are different camp to when the backset is added. In most bourbon distilleries it is added during mashing. At Buffalo trace, they add it to the mash corn immediately before pitching yeast.

Buffalo trace isn't even running their Dona Tubs anymore. They buy all their yeast.

They turned their yeast room into a separate small distilling company with its own craft size still.

[Denver Distiller]

When you are fermenting in 35 foot deep 80000 gallon fermenters, one contaminated batch is very costly. Risk reduction is the way.

That's true, but by way of comparison to wine and beer production, that's distiller's beer is always infected (no process is sterile, obviously). It's a question of degrees. There's a reason that whiskey producers use open wooden fermenters. It's not just because they look nice for tours.

But there's only so much that lactobacillus can do in 3-5 days when the big boys are also, obviously, pitching healthy yeast.

[Sherman]

Well, of all the distilleries I've been in, I can only name three which had wooden fermenters.

Of those, none had all wooden fermenters. Most of their production fermenters are stainless.

It has been explained to me by several distillers the steps to prevent unexpected contamination.

1. acidification while too hot for contamination

2. very rapid cooling in a closed system before placing in the fermenter.

3. inoculating with good known mono culture type lacto.

4. using as much as 1.5% mash quantity in active culture.(source Jim Rutledge Four Roses)

5. very active fermentation forms a vapor seal with the co2 above the mash.

6. mash is distilled as soon as active fermentation is finished. no settling and clearing period at all.

7. caustic and steam in the fermenters between batches. Even the wooden ones.

All these precaurions together prevent unwanted contamination. From the results that the major distillers are accomplishing, they would be a good example to immitate as far as cleanliness standards are concerned.

[cowdery]

We don't have tours often, but when we do, I always explain that sour mash is a poor man's way of acidifying the mash. You've got a nice, cheap (read: free) source of a liquid that's low in pH, and it can drop the mash pH to acceptable levels by using that sterile stillage.

What's also nice, and the reason that you use it in prepping yeast, is that stillage still contains yeast, or more specifically, all the minerals, nutrients, etc. that were consumed by the yeast during fermentation. What was inside the yeast when it was living, is now floating in the stillage after the boil. It's all right there, ready for the new yeast to consume.

So really, it's a combination of cheap acid and free yeast food. Pretty neat, actually.

JohnD, the lactic acid that was produced by any lactobacillus strains that worked in the fermenters will be present in the stillage, but, obviously, the bacteria itself will be deader than dead. So yes, you'll be recycling both yeast and lactic acid, but they won't be alive.

This may be the best explanation of sour mash that I've ever read and I intend to steal it at my first opportunity. I might say "cost-effective" rather than "cheap," though.

I'm getting a lot out of this thread. I also love the idea that the early association of geographically-specific yeast strains with the corn-based whiskey that came to be called bourbon gave Kentucky-based distillers an advantage over distillers that tried to make bourbon in other places. Is that how wild yeast strains are distributed? I thought they were more associated with the local flora. Is Central Kentucky a micro-climate of some sort so that the yeast strains abundant there are present nowhere else?

It has long been believed that Kentucky's advantage was limestone water, to the point where it became a source of mockery. ("It's the waaa-tuh, Sir.") Who knew Kentucky also has better wild yeast?

Jumps-to-conclusions abound in the online world and something offered as "a" reason for something suddenly is construed as "the" reason. Similarly, I never said microdistilleries should or must make yeast. My contention is that if you want to be "craft" and especially if you want to say you are more "craft" than the big guys, you should be willing to say what makes you "craft" or "more craft."

For example, it is fair to claim that making your own yeast from scratch makes you more "craft" than someone who doesn't. But "craft" isn't the only way to be a cool micro-distillery, but if being "craft" is important to you, tell me honestly and accurately what makes you "craft."

[grehorst]

The geographic relationship of yeast is very interesting. Our distillery in Milwaukee is less than a mile away (as the yeast flies) from the location of a whiskey distillery that opened in 1882 as Meadow Springs Distillery and later was known as National Distilling. During prohibition they focused on the yeast production business. That company became Red Star Yeast which produced yeast in that same spot until about 5 years ago. Of course we have historically had a ton of breweries here as well. I've never heard anyone give credit to the success of these products because of the local flora but with the roots of one of the worlds largest yeast brands having been established here it makes me wonder...

To get an idea of how much yeast they produced here, Red Star was the city water utility's largest customer. Number two was Miller Brewing. When Red Star closed everyone's water bill went up significantly.

[Denver Distiller]

I'm getting a lot out of this thread. I also love the idea that the early association of geographically-specific yeast strains with the corn-based whiskey that came to be called bourbon gave Kentucky-based distillers an advantage over distillers that tried to make bourbon in other places. Is that how wild yeast strains are distributed? I thought they were more associated with the local flora. Is Central Kentucky a micro-climate of some sort so that the yeast strains abundant there are present nowhere else?

If we're talking lactobacillus, the real culprit is the grain. That stuff rides into the distillery with the malt and grain. And we're not talking about Belgian coolships the roof of a brewery for a few days w/o pitched yeast, or a spontaneously fermented high-ester Caribbean Rum that's sitting outside in a concrete lined pit. We're talking about a 3-5 day grain fermentation with healthy saccharomyces (distiller's yeast) before it's literally vaporized. Airborne contaminants don't have much of a chance with these circumstances.

Where the lactobacillus does have a chance is by direct addition to the mash en masse. And, of course, that's just what happens when you mash in. You're adding quite a bit of lactobacillus in that 10%-20% portion of the grist in the form of malted barley directly into a FAN rich mash. That makes for happy little buggies if you let them have their way. In addition, smaller distilleries (and breweries, for that matter) will have loads of malt dust (different from regular airborne particles), rich w/ lactobacillus, in the air because they usually didn't separate their mill rooms from those open fermenters. We don't at our shop, and it's specifically with the intent of encouraging lactobacillus growth.

So really, IMHO, the question is, where did these old TN, KY, and PA distilleries buy their grain from? More specifically, where did they buy their malted barley from, and where was it malted? That's a more likely culprit, IMHO, of lactob. activity.

[delaware_phoenix]

I think it's a really interesting question as to what kinds of yeast are in what geographic areas and how those specific yeast effect (positive or negative) flavor in whiskey.

It has to be remembered that when it comes to bourbon, it really began as corn whiskey with the addition of small grains such as rye and/or wheat. Corn was not as good a crop as rye or wheat in a place like NY, PA, and perhaps other Eastern locations north of Virginia that had poor, rocky soil. I suspect that KY water was very important as it has a good source of minerals without a lot of iron or sulfur. Because of the profundity of the KY soil, farmers were able to grow not only lots of corn, but also rye and wheat. So the small grains that became an integral part of bourbon (as opposed to corn whiskey) were readily available. Other places with good soil, may not have had the proper climate for those small grains. The Carolinas and Georgia are not good for growing rye or wheat.

In the 1820's, there was no way to acidify the mash except through backset or letting a lactobacillus infection into the mash before pitching yeast. Adding backset certainly was the fastest. They didn't have a way of knowing they were "acidifying the mash", but they called in souring the mash. And they knew it created a better environment for the ferment. Back then, there wasn't a chemical industry from where they could order citric acid, etc.

I can list some things and ways that my distillery differs from the big distilleries.

1. Scale, a 50 gallon still vs 60,000 gallon stills

2. A traditional pot still instead of a column still

3. No use of extra enzymes from the chemical industry

4. Mashing by hand in small batches like it was done in the old days

5. Open system for mashing and fermenting

6. No use of caustic or steam in the fermenters (some TSP at times for cleaning)

7. No concern for efficiency

8. Not owned by a faceless corporation

I bought a nice commercial liquid ale yeast once, but I'm pretty sure I don't have a monoculture anymore. And I have a mason jar of yeast, so maybe that means I use "jug yeast".

There may well be other ways I differ from the big distilleries, but I don't know enough about them to know how I differ. A lot is a matter of scale, and I think small scale is important. It was the way things were in the distilling business in the beginning. Whether that's better or not is up to each person to decide.

[cowdery]

Today all of the malt comes from Milwaukee but historically, I don't know. Both Louisville and Cincinnati got big off of German immigration. Both cities had dozens of breweries. Were there also maltsters there, or were they closer to the barley crop, and where was that?

Most bourbons, of course, are 3/4 corn and most of that was local or nearby (i.e., Indiana, Ohio), as it still is. But the corn gets cooked, i.e., boiled, so only buggies that get airborne after milling would be available. Rye initially was local but after the railroads cut transportation costs, most wheat and rye growing moved further west. Cooking temps are reduced for the addition of rye/wheat, then further reduced for the addition of malt. Of course, distillers typically try to use as little malt as possible to save money. I know Brown-Forman specifically adds lactobacillus and I assume others do too.

Wooden fermenters are now pretty rare. You mostly find them only where tourists will see them. I believe Woodford Reserve is the only major distillery that has only wooden fermenters. Places such as Wild Turkey and Four Roses that still have a few say they probably won't replace those when they finally wear out, due to the cost.

Excluding Woodford Reserve, the newest distillery in Kentucky also has the largest fermenters: 123,800 gallons. It's Heaven Hill in Louisville and they have nine of them. Their beer well is even a little bigger, at 124,720 gallons.

Parker and Craig Beam wanted to continue to use their jug yeast but Bernheim, built in 1992, never had a yeast room and Max wouldn't spend the million dollars it would take to build one, so they got the yeast company to create a dry version of their proprietary yeast. Their 'yeast room' consists of a big refrigerator for the dry yeast plus a couple tanks to hydrate it in.

[delaware_phoenix]

Here's a question: prior to the Civil War where was barley grown? If not in KY, where? And if barley wasn't originally available, was corn malted (probably yes) and what that a reason for the small grains: they were malted and provided greater conversion (and therefore higher yields). Later when malted barley became available, the small grain could simply be used without being malted.

Anyway, just a thought.

Typically the corn is milled first, then cooked as part of the mashing process.

[Sherman]

Here's a question: prior to the Civil War where was barley grown? If not in KY, where? And if barley wasn't originally available, was corn malted (probably yes) and what that a reason for the small grains: they were malted and provided greater conversion (and therefore higher yields). Later when malted barley became available, the small grain could simply be used without being malted.

Anyway, just a thought.

Typically the corn is milled first, then cooked as part of the mashing process.

In the book 'The New History of Kentucky' By Lowell Hayes Harrison, James C. Klotter Page 138

Among the 15 slave states in the Union in 1859, Kentucky ranked first in the production of rye, barley, horses and mules

There were several malting houses in Kentucky. In 1855 EW Herman had a really large malting operation. He later partnered with JH Pank. In 1870 they formed the largest malting house in the US. The Kentucky Malting Co. had a capacity of 500,000 bushels on the floor. Which was larger than JH Pank and CO their sister company in Chicago. The business dried up when the spring barley took over production in the midwest over the winter barley grown in KY.

Until 1961, Kentucky exported more beer than it consumed.

[Denver Distiller]

Outstanding find, Sherman!

That certainly lends credence to your point, don't you think?

[Ballast Point Spirits]

We have been using our house Ale strain which was originally an English Ale yeast. It has been working great in our beer for 13 years so we figured we would use it in our whiskey as well. The reason to culture your own, which is done by thousands of breweries nationwide, is economy and availability. We have yeast being made every day and reusing it is very simple. Harvesting from a conical bottom fermenter and adding it to wash takes but a few minutes and saves hundreds of dollars a month. The whiskey distillers in Kentucky that use liquid yeast instead of dry yeast are some of the few in the distilling business that think the strain has an effect on the flavor of the finished distillate. How could it not, as brewers we see this across the board in the broad range of beers we make. Never mind the sour aspect of Kentucky mash for now, just the yeast alone is responsible for all sorts of flavors in the finished product. This is affected by fermentation temperature as well and many distilleries don't try to moderate heat produced during fermentation and the result may or may not be something you would want to distill. Some distilleries are not set up to handle yeast propagation or harvesting and doing it may result in more problems that it is worth, but a working brewery/distillery has everything it needs right under the same roof.

[Sherman]

I have been chatting with Mike Veach on facebook about this subject and his perspective is a good alternative.

I still wonder if it was the quality of the yeast or the quality of the person growing the yeast. It seems to me that I have read that the old distillers often rejected a yeast they had started, meaning that yes there are good yeast in Kentucky. but also some very bad ones and it took a master distiller to know the difference. In my opinion, what made Crow and others of his era "Master Distillers" was based upon this ability to know good yeast from bad as much as the actual distilling of the whiskey. You can do the distilling process perfect, but if the yeast made bad alcohol, it is not going to make bad whiskey.

There is a lot of merit to his statement.

I have been doing a bit of research as to the difference in domesticated and wild sacchromyces cervesea.

one research article I found was this..

We have surveyed DNA sequence diversity at five loci in 81 strains of S. cerevisiae that were isolated from a variety of human and natural fermentations as well as sources unrelated to alcoholic beverage production, such as tree exudates and immunocompromised patients

Their conclusion was interesting.

The four strains associated with fermentations, three of which were isolated from traditional African wines, show the greatest diversity and represent some of the oldest lineages. This raises the possibility that S. cerevisiae was domesticated in Africa and that most vineyard and saké strains were derived from a domesticated African strain. If so, one would expect clinical and natural isolates to be more closely related to strains isolated from vineyards, which have a cosmopolitan distribution compared to strains from traditional African wine. Clinical and natural isolates, however, show no obvious relationship to strains associated with manmade fermentations.

Although the genealogical relationships among strains of S. cerevisiae show that the species as a whole is not domesticated, the data do support the hypothesis that some strains are domesticated. Based on the low levels of diversity within vineyard and saké strains and the clear separation of these two groups, we propose two domestication events, one for yeast used to produce grape wine and one for yeast used to produce rice wine. When might these events have occurred? Domestication would have occurred after the divergence between the vineyard and saké strains but before differentiation among the vineyard and among the saké strains.

...the estimate for the divergence time between the two groups is approximately 11,900 years ago, and within the vineyard group and saké group is approximately 2,700 and approximately 3,800 years ago, respectively.

Citation: Fay JC, Benavides JA (2005) Evidence for Domesticated and Wild Populations of Saccharomyces cerevisiae. PLoS Genet 1(1): e5. doi:10.1371/journal.pgen.0010005

This really makes a case for the fact that the yeast follows human activity and the raw materials used for fermentation. Which would mean I was wrong about it being the Kentucky Yeast.

It would seem that once a work area is contaminated with the domesticated yeast, the attempt to catch yeast will continue to catch the domesticated variety.

I also found a lot of history that demonstrated that the distillers of the late 1700's were quite adept at growing, drying and preserving yeast. The prevalence of "stock" yeast is a very old industry that was listed on histories of industry back to the 1500's in the Americas. The brewing/baking yeast was probably brought here on the Mayflower. So, is there really "Wild" yeast to catch? Our fruits and grains may have been contaminated by the domesticated varieties in pre-history. The isolates from tree saps were significantly genetically different.

There was also many accounts of the native Americans making maize based chicha and many immigrants making the same thing instead of barley based beer. One history specified that the native Americans in the mid Atlantic states were very well versed in malting and brewing maize before they encountered the first Europeans.

For an extremely interesting read here is a very well written and cited piece on yeast in the Scotch Whiskey industry.

This is an excerpt from the book "Whisky: Technology, Production and Marketing (Handbook of Alcoholic Beverages)"

Inge Russell, Charles Bamforth, Graham Stewart

http://www.hotelmule.com/management/html/88/n-1788.html

The book sells for $598 on Amazon.com

[delaware_phoenix]

I remember reading that in many wineries the actual wild yeast is not S. cerevisiae. There are many other genus of yeast, and many naturally appear on ripening fruit. Many of the old (early 1800's) books and notes mention the use of ale yeasts, so there's no reason to think these weren't used, perhaps in conjunction with natural fruit yeasts. And these yeasts may well vary geographically.

Thanks for the history on winter barley Sherman. Yet another way for a craft distiller to differentiate themselves: by using historical varieties for their grain and fruit, regardless of whether they might be efficient or make you oodles of money.

[Denver Distiller]

. So, is there really "Wild" yeast to catch? Our fruits and grains may have been contaminated by the domesticated varieties in pre-history.

The short answer is: absolutely. Yeast are fickle little buggers. I had a strain of hefeweizen yeast that I used for years that would generate a pretty big pear note, but only when I shorted it on oxygen in the log phase. The pear aroma, if you'll pardon my nerding out for a moment, is a compound called iso amyl acetate. It would also lose the ability to generate iso amyl acetate after about three generations.

Some yeast strains can be repitched many times without major mutation, and some change after only a couple generations. So the stuff may have the same DNA, but will yield completely different flavors/congeners based on either mutations it has undergone, or small changes in environment.

Two-tenths of a pH point difference during pitching can change the performance of some lager yeasts I've worked with pretty dramatically.

So yeast you yank out of the air can behave totally differently than your main culture.

On another note, certain malting procedures can leave the kilned malt with elevated lactobacillus, whether intentional or no. I can see that being a thread through KY distilleries.

Obviously, this is just fun speculation.......

[Sherman]

I remember reading that in many wineries the actual wild yeast is not S. cerevisiae. There are many other genus of yeast, and many naturally appear on ripening fruit. Many of the old (early 1800's) books and notes mention the use of ale yeasts, so there's no reason to think these weren't used, perhaps in conjunction with natural fruit yeasts. And these yeasts may well vary geographically.

Thanks for the history on winter barley Sherman. Yet another way for a craft distiller to differentiate themselves: by using historical varieties for their grain and fruit, regardless of whether they might be efficient or make you oodles of money.

My great uncle Leo, moonshiner and bootlegger, used to start his yeast in the fall and make enough to last all winter. I was hanging around his place when I was 7 in 1969 and saw him make his yeast. He would used store bought Blue ribbon malt extract as his base. He would boil a small amount and put it in a pint jar with a lid and put it in the creek to cool down. Once it was cool enough for him to handle, he would take a crabapple and dunk it in the pint jar. He would throw the crabapple away.

That jar fermented in 2 days. He pointed out the settled residue on the bottom of the jar and told me that he was going to make a whole bunch of it. He then made what seemed to be 5 gallons of wort and put it in a water bottle carboy. The pint went in that and in 2 days it had a 1/2 inch in the bottom of the carboy. I seem to remember him dividing that among what seemed like 20 carboys. In these he used a really thin wort and used fish pumps to blow air in the half full carboys. He would add molasses everyday. Eventually he had a whole lot of yeast. He distilled the fermented "beer" from all the carboys. It was a weird tasting malted rum. He pressed and dried the yeast but I don't remember seeing how he got the liquid out of it. He passed away when I was a teenager. I asked him where he learned to do that. He told me at Sterling brewery in Evansville IN. At that time yeast was really expensive.

Except for the crabapple I pretty much did the same process at Charles Medley Distillery when I worked there in 1982 until I got a job repairing car stereos(lots more money). Roy and Thomas Payne had the patience to answer every stupid question I had. I was just the grunt who carried the bags of whatever and cleaned the tanks and tubs. The distillery closed in 1992 the year I started my engineering degree.

It is becoming quite a tourist distillery now by the name Angostura.

Here is a nice slide show of its history.

http://www.authorstream.com/Presentation/CPTDerek-184376-charles-medley-distillers-kentucky-histo-cmdk-bourbon-distillery-history-utube-business-finance-ppt-powerpoint/

Denver Distiller I was typing this up as you were your reply. I think you must have seen it all by now and on a completely different scale that I have seen.

[JohnD]

Sherman, as of the post you just put up with your grandfather's story this is my favorite thread I've ever seen on the forum.

Thanks to you and Denver for some really great info.

Delaware, it is really common to use S. bayanus in wine fermentations. It makes great flavor and fast.