The Yeast of my worries

[bourbonv]

After attending the Four Roses event with the Bourbon Society, I have been thinking about yeast and its effect on the flavor of bourbon. Often we credit the rye in a bourbon with the spicey characteristic of bourbon, but that ain't necessarily so. Four Roses has two mash bills - 1 high rye and the other about the standard amount of rye. They have 5 yeast strains. That makes for 10 different whiskeys.

Now if the rye was responsible for the spicey flavor of bourbon, then all of the high rye whiskey would be spicey, right? Well that is not so. There are a couple of their high rye formulas that are not spicey at all. They are more fruity and candy like. The lower rye, higher corn recipe should not be spicey if rye is responsible for spice, but there is a very nice whiskey in that group with some sweet spice flavor.

Now my favorite bourbon that we tasted that day was a high corn mash bill with a yeast that gave it a rich berry/apricot fruity flavor with a touch of vanilla and caramel. Now then you would say that yeast makes fruity bourbon. Well yes it does with that mash bill but when put to the rye mash bill there was some fruit, but then there was sweet spice and other flavors. It makes me wonder what this yeast would do with a wheated bourbon. Would it be a rich fruity bourbon or maybe spicey. The yeast needs more study for me. I want to do this whole tasting over again a time or two to see if I can figure it out.

Now as a historian, the importance of yeast leads me to some other questions. Is yeast like other species and different strains live in different climates? Is that what made Kentucky and Pennsylvania superior distilling areas - there yeast strains happened to be the best flavor makers for the type of whiskey made there? I think I am going to experiment this summer and capture some wild yeast in Kentucky and mash some corn meal and see what happens.

[Mike]

Very interesting, Mike. In my limited experience with yeast and brewing beers, the yeast, when it is most noticable, adds fruity flavors.

Maybe Brewer, or our friend Logical Frank, who has a lot more experience than I do with brewing, can share his knowledge and experience with yeasts.

It would also be interesting to know if the yeasts intended for making beer are different from the yeasts intended for making bourbon or other distilled spirits, as I assume they are.

[brendaj]

Mike,

I want to do this whole tasting over again a time or two to see if I can figure it out.

Me too, me too!
I had two distinct favorites. I'd like to see if that would still be the case.

What would be pretty cool, get jars of the different yeasts and taste those side-by-side as well. I managed to stick my finger in two different yeast tubs, the floral just jumped out of one of them.

That was a great trip.
Bj

[gillmang]

First we must ask: what type of yeast is used to ferment a bourbon mash? Is it top-yeast or bottom-yeast? Distiller's yeast (dried, jug, doesn't matter) has to fall into one of these classes.

I believe distillers use top yeasts, which work on the top of the ferment at warmer temperatures than bottom yeasts. Bottom yeasts tend to flocculate and settle in the mash and work at colder temperatures. They were developed from yeasts which fermented beers in cold caves in Germany. These yeasts would settle down in the vats and the ferments were prolonged and more thorough than quick-acting top ferments (lasting 3-5 days and Bob's your uncle - those lager caves and later refrigeration emulations could mature beer for months). Top yeasts tend to be not as pure strains and often give beer a tart, estery taste. Bottom yeasts are cleaner (because not exposed to the air as much) and produce a less fruity, rounder beer - the trade-off for their better stability is less complexity of flavor. Think of Heineken vs. Sierra Nevada, say.

There are innumerable top yeasts and bottom yeasts too and each will influence the beer being distilled, as they do the taste of beverage beer. If you are talking an apricot-like taste, that suggests to me an estery top-yeast.

I can complicate things by noting that you can use bottom yeasts but ferment them warm (around 70F - lager yeasts work much colder, generally) and the warm temperatures help produce esters in the beer.

All yeasts were wild originally and have been bred or isolated to produce the best tastes for the purpose needed.

So, are distillers fermenting cold in covered vessels or are they still using open fermenters at ambient temeratures like the old ale brewers did? (Ale is a term for the old top-fermented beer). If the latter, the fruity taste of their beers will get into the distillate.

In a hot climate, top-ferments sour quickly (because the yeasts get contaminated by wild strains), which is why beer brewing was not done in summer until refrigeration was made possible. However, distillers' beer doesn't last long enough for spoilage to be a problem, a little tartness is no obstacle since the beer will be turned into alcohol quickly. Still, it is noteworthy that distilleries did not used to operate in summer, probably for the same reason breweries did not. No one wants a whisky made from a putrid beer, which is what can happen to a seething yeast mass at 80F.

To understand yeast in distilling you have to understand beer first. The yeasts are the same in both cases (in terms of their function - consuming the sugars in a ferment to produce ethanol and CO2 - in distilling the C02 is allowed to lift off harmlessly).

I doubt yeasts had particular character in KY and Maryland - they exist everywhere and in a variety of forms which keep mutating endlessly. Nor did KY and Maryland become renowned for beer brewing, although PA did, true. I think the tradition of stilling brought to these places was the predominant influence in the whiskey culture that developed.

Gary

[EllenJ]

Wow, Mike. In all the (OhMahGawd, has it really been years???) I've known you, this may be the most important new angle (of several) you've ever noted. The importance of the (dominant, because really there are several involved) yeast colony has always been obvious, but your comments on the degree to which that affects the flavor really brings it into focus. I'm very anxious to see how your experiments go. If you take care to make them non-subjective (I know... I know... we enthusiasts prefer subjective -- we just wanna know if it tastes good) they have a potential to be definitive in describing a process no one else has approached.
Way ta' go, Professor!!

[gillmang]

John, I agree with you, and the importance of yeast flavor has been highlighted now through Mike's ability to taste on the spot bourbons made from different yeasts.

But there has long been discussion of this here, and it originated some time ago (maybe during one of the periods you were not as involved with the Board).

I speculated then, for example, that in Maryland, the English tradition of fruity-tasting, top-fermented beers may have carried over into distilling with the result that Maryland whiskey was notably estery. Straight whiskeys aged 5-10 years may have brought out this characteristic. Later, rectifiers and blenders may have emulated the taste. In other words, the fruity blended taste of your 1900 Melvale may have originally been a straight whiskey taste at its height of quality (and that Melvale may be a straight anyway, possibly lightly sweetened).

In Kentucky, even if (as I assume) top-yeasts continue to be used to this day, distillers may have selected, through error and trial, relatively neutral-tasting strains. Maybe they felt the market required this.

In practice, probably each house had its own practices and tradition but today I would say most Kentucky whiskey does not seem notably fruity. Old Forester 100 proof may be an exception, and there are others of course including some of the whiskeys from Four Roses.

Gary

[bourbonv]

From what I could tell at Four Roses, the characteristics of the yeast came through somewhat in the dona tub, more so in the beer and of course strongly in the distilled spirit. Even so they are also changed by the aging process as well. Every step of the way changed flavor, but one of the main sources of the flavor was the yeast strain.

So Gary,
I know yeast has hundreds of different strains. My question is are the same strains found wild in Germany found wild in the United States? Both countries have oak trees, but they are a different variety of oak tree. Does the same fall true for yeast? Is the wild yeast that dominates the Kentucky landscape a better yeast for making distilled spirits from grain than the yeast found in Greece or Italy where wine is more commonly made and distilled? Could the wild yeast be one of the advantages that Kentucky has had over other places when it comes to making bourbon?

[gillmang]

Mike, I cannot answer that as a scientist would, but my understanding is wild yeasts everywhere are similar in their characteristics. Here is my evidence. There is a Belgian style of beer which is fermented solely from wild yeast. The style is called lambic beer. The bottled version is called "gueuze" (the term appears related to the term "gush" for the spritzy effect it has). The open fermenters are situated in the top floors of the breweries and a slatted roof allows the yeast in. The beers are quite cidery and "wild", but are not putrid (of course) or undrinkable by any means - they have a refreshing tartness of their own (kind of like sparkling hard cider). You may want to pick up a gueuze at Liquor Barn, if you do, buy one that is not flavoured (although the cherry one is good too). Mort Subite makes a good unflavored gueuze and that is available there I think and there are probably others (Lindeman makes one, Cantillon, etc. - ask and the store will (or should) know).

Anyway, I have read that gueuze brewers have said, or some have, that gueuze can be made anywhere in the world. Even though there is a lore about the fabled wild yeasts of the Senne Valley in Belgium, where these beers are made, in fact the same kind of beer can be made anywhere. There are a couple of American brewers making wild yeast beers, New Glarus is one I believe. Again Liquor Barn can direct you.

If wild yeasts are that similar, I doubt local strains could have made much difference in Kentucky. Had they been unusually good, commercial distilling would have taken place during the summer in Kentucky before refrigeration became common, but it didn't.

Today, all yeasts are selected in some way execpt for wild yeast beers. See in the American and Canadian whisky chapters in "Alcohol" the discussion of yeast. The chapters are included at http://www.scocia.com under "My research" (the site is by a person who studied at the renowned Watt-Heriot school in Scotland, it has a world reputation in brewing and distilling science).

Gary

[bourbonv]

Gary,
What you say might very well be true if theonly grain used is barley malt. My question is there a yeast strain that really loves corn in Kentucky that is not found elsewhere, and does that yeast make great whiskey alcohol?

[EllenJ]

...I speculated then, for example, that...

Gary, with all due respect to folks like you, me, Chuck, Sam, and others who love to speculate, there is a HUGH difference between that and what Mike has been able to do. And that's because his opportunity came from Four Roses, rather than one of the other distilleries. What makes Four Roses different isn't that they're better than others, it's that they actively work with several combinations of yeast strains and mashbills.

All of the others have one, maybe two, yeast strains which they consider to be "their distinctive yeast". Distillers like Dave Pickerell or Jimmy Russell are intimately familiar with their own yeast, but have no long-term hands-on experience working with others. Distillers who have spent years working for multiple distilleries, like Jerry Dalton or Bill Friel have a broader knowledge base. But none have the range of combinations that Jim Rutledge enjoys (and Ova Haney before him).

And for Mike to be able to make empirical side-by-sides there is another degree of magnitude above anything we might speculate about.

[Bourbon Joe]

I would think that Four Roses must have a monumental job keeping the five yeast strains from contaminating one another. I would think that cross contimination would be very prevalent and that great pains must be employed to keep them seperate. What do you all think?
Joe

[LogicalFrank]

Maybe Brewer, or our friend Logical Frank, who has a lot more experience than I do with brewing, can share his knowledge and experience with yeasts.

Well--if you're gonna call me out...

I think bourbonv has a very excellent point. I've actually argued many times that rye itself does not provide that much spicy flavor in beer. People will swear up and down that it does but I've made some rye beers w/ the specific intent of showcasing the rye and while they were all good, I didn't necessarily find them to be all that spicy specifically. (My favorite recipe so far.) Personally, I think people's expectations based on the culinary uses of rye color and change what they perceive in the beer. I know the first time I tried a rye beer I was surprised it didn't taste like caraway seeds.

[Mark]

I've got to agree as well... While at Bob's beer place many months ago we both bought this big ass bottle of beer called Hot Rod Rye. I was expecting I guess what one would expect from hearing the word rye but it wasn't. It was actually a kind of smooth and not so in your face beer that I quite liked... I mean yes it was different but not ryed up and spicy like I was expecting.

[LogicalFrank]

I would think that Four Roses must have a monumental job keeping the five yeast strains from contaminating one another. I would think that cross contimination would be very prevalent and that great pains must be employed to keep them seperate. What do you all think?
Joe

Lots of American craft brewers use multiple strains of yeast to good effect and w/o contamination. Just for example, I know that Goose Island here in Chicago must use at least a regular ale yeast, a lager yeast, a Belgian yeast and hefeweizen yeast and they use different ones all the time for specialty beers. (This all just a guess based on the beers they brew.) Sanitation is critical in keeping these from contaminating each other but sanitation is always critical so there's not much special you'd have to do aside from needing more facilities to store the actual yeast.

[gillmang]

Some points: no question, John, that Mike's experience at Four Roses is an important validation of the effects of different yeasts in the final distilled product and in the dona tub too.

But when you know that peat, or apple flavor (esters), say, come over the still into whisky and applejack or Calvados, one can see that distillate flavor will be affected by the fruity or other tastes of various beers. This is shown too by sampling FR Small Batch which is noticeably estery in an apricot/orangey way (as compared, say, to FR or FRSB).

Gary