This might be a dumb question, but I'm wondering what exactly makes different yeast strains unique, and whether these differences are natural or by design. For example, certain Belgian-style beers (not even getting into lambics and sours here) have a distinctive mustiness, funkiness, fruitiness etc. that's attributed to the yeast strain used in fermentation. By contrast, take an American IPA or pale ale. There is absolutely zero yeast presence that I'm aware of. I can taste/smell the malt, hops, and water, but not the yeast. First off, I'm not even sure the term "Belgian yeast" is a legitimate, meaningful term (though I use it all the time as a descriptor). I mean, does it have a passport or something? Is this term used to describe/summarize decades/centuries of continuous culturing of yeast strains used in traditional Belgian beers? Or is there something unique about the geography/climate/zoology of the Belgium region itself that gives these yeast strains their unique characteristics? As for the yeast used to ferment IPAs, American pales, etc., is this because the yeast strain used in some beers is essentially a "neutral" ingredient, which ferments the wort and converts sugars into alcohol but imparts zero or virtually indetectable traces of its own taste/aroma to the profile of the beer? Is it just because it's hidden behind powerful hops? Or is it because I'm "used to" the yeast used in certain beers and so the Belgian yeast strains are more noticeable only because they are so different? Sorry for the rambling post, hopefully the question is clear. Thanks and cheers!
Kinda what I fiqured but a lot of people dont go back to the old site. Just trying to be helpful. Cheers!
How about this? Is this what you are looking for? http://www.beer-brewing.com/beer-brewing/brewers_yeast/yeast_strain_selection.htm Cheers!
Yeah, I know, I appreciate it. I guess what I'm getting at is, is the yeast strain used in certain beers (IPAs and pales, probably others) truly neutral, for lack of a better word? Or does it actually constitute an important part of every beer's profile and for some reason I'm just completely overlooking it?
Yes, I would say so. Look at any brewing site and they show how many different yeasts for how many different beers? I would think a Belgian IPA is such because of the yeast. Each beer tastes different per the yeast strain used. I think more brewers could help me out here, but I think in my head at least the yeast does make a difference. Cheers!
Maybe this analogy won't work, but compare beer to music. I'd liken the yeast in certain beers (SNPA or Two Hearted for example) as the silence between notes. It's there but you don't hear (taste) it. The yeast in Duvel or Westmalle Tripel, OTOH, seems like an instrument and sound unto itself. Does that make sense?
Uhh, I'll take a stab at it off the top of my head. The different strains of yeast have diverged over time to develop different slightly different cellular machinery and a ton of different mutations in their DNA. They pretty much operate in the same fashion (broadly: yeast ferment sugar to alcohol and CO2) but as the DNA mutates, this can cause changes in proteins as well. These proteins are responsible for the yeasts metabolism like the reaction mentioned above. Over long periods of time these mutations build up and cause a noticeable difference to us in what the yeast produces during fermentation. Each strain will produce slightly different concentrations of many chemicals (alcohols, people often mention esters), therefore a different taste profile. EDIT: To build on it a bit further, the environmental factors in Belgium can certainly make a difference as to how the yeasts evolved. I am also assuming that many of the Belgian classic breweries are old and have used the same yeast in the same way for many years. This would cause the yeast to adapt over a long period of time to that breweries atmosphere (the yeast with the most favorable traits will survive). Belgian yeast strain is a legitimate term as well as American yeast strains. They have evolved in different directions and produce different chemical profiles in fermentation. Temperature of fermentation also plays a HUGE role in altering a yeast's beer flavor characters. Stress to the cells will alter chemical by products of fermentation. The main American Ale Yeast strains that have been cultured and isolated have a very neutral flavor profile (allowing malt and hops to really dominate), they probably just give off much less of certain compounds we taste from yeast in beer. The opposite is true for the more flavor bearing yeast strains. I also just found this: http://genome.cshlp.org/content/10/4/403.full Wordy science article about different yeast in wine, bread, etc.
Perhaps a better analogy would be that of a car/motorcycle engine. Some large engines make lots of noise, some kick out crazy smoke, other sports cars give off a high whine and finally there are some electric engines that though they still power the car make very little noise. Some people buy a Harley because they like the noise the engine makes. Yeast eating sugar to create alcohol is an incredibly complex process and there are all sorts of byproducts which can be increased or decreased depending on the strain, brewing practices... So all that is to say, that yes, some yeast is more "neutral" meaning it contributes very little in the way of flavor or aroma. And yes, "Belgian Yeast" is an appropriate term, it primarily refers to yeasts that were historically developed in Belgium however nowadays that same yeast can be propagated in a lab in California and it will still be Belgian yeast because it displays the characteristics that we have attributed to "Belgian Yeast".
You've probably noticed the beers from some breweries will some of the same characteristics across the lineup. You may notice it more in some styles (blondes, ambers), and less in others (IPAs, big stouts, BBL aged stuff). Some breweries will just use a single strain of yeast for most of their brews, which is why sometimes you won't see lagers or Belgian styles from those breweries. Individual yeasts will give different tastes and aromas, they may just be hidden behind other flavors. Imagine, if you will, an IPA made with a Hefeweizen yeast (somebody has probably tried this, I wonder how it came out), it would probably take a lot of hops to hide the banana.bubblegum/clove, wouldn't it. Perhaps brewers use yeasts that won't distract attention away from the hops in IPAs? Not really an answer for you, as much as some random thoughts.
I like this analogy. I'd only add that there's no "right" or "wrong" or "better" or "worse" yeast (just as there's no right or wrong engine), it all depends on what you're trying to achieve. I just wanted to confirm that the yeast used to ferment certain beers is much less a part of that beer's flavor profile. Because alternatively, it could be like living next to a freeway; after a long enough time you stop hearing it, and only notice an absence of noise after you leave. And yes, I understand that "Belgian" yeast doesn't have to literally come from Belgium. It's more like obscenity: I know it when I see it.
Exactly, I can rev my subaru station wagon and it will make more noise, just like a brewer can ferment hot and get a bunch of esters, though they might not taste too good.
One interesting feature is the yeast POF gene, named for "phenolic off-flavor". This gene function has been selected against over centuries of brewing and is inactive in most brewing strains. It encodes an enzyme that is part of a biochemical pathway for producing a variety of phenolic compounds. It is active in German wheat yeast and many Belgian yeast strains and results in the clove, spice, smoke, vanilla, pepper, and other phenolic flavor compounds associated with these styles.
I will approach your question from a homebrewing perspective (since I am a homebrewer). Firstly there are lots of different strains of Belgian yeasts (a ‘boat load’ when you include the more esoteric aspects of Brett yeast strains and the non-yeasts of Lactobacillus that is used to make sour beers). So, let’s just discuss the more ‘standard’ Belgian Ale strains. There are a number of different Belgian Ale Strains which each will produce their own unique blend of ester and phenols flavors. A useful table which provides information on Belgian yeast strains (and the breweries they come from) is on the Mr. Malty website: http://www.mrmalty.com/wyeast.php From Mr. Malty, below is a list of Belgian Ale yeasts from the yeast vendor Wyeast (which details their strains via numbers; e.g, 1214). The WLP numbers are the White Labs equivalent strains. 1214 Belgian ale Chimay WLP500 Trappist ale 1388 Belgian Strong Ale Duvel (Moortgart) via McEwans WLP570 Belgian Golden Ale 1762 Abbey II Rochefort WLP540 Abbey IV Ale Yeast 3522 Belgian Ardennes Achouffe WLP550 Belgian Ale Yeast 3711 French Saison Brasserie Thiriez 3724 Belgian Saison Yeast Saison du Pont WLP565 Saison Ale Yeast 3725 Biere De Garde Soy-Erezée, Belgium n/a 3726 Farmhouse Ale Blaugies, Belgium n/a 3763 Roeselare Ale Blend Rodenbach n/a 3787 Trappish High Gravity Westmalle WLP530 Abbey Ale Yeast 3864 Canadian/Belgian Ale Yeast Unibroue 3942 Belgian Wheat Esen, Belgium (De Dolle) n/a 3944 Belgian Witbier Hoegaarden/ Celis White WLP400 BelgianWit Ale Yeast So, each of the above yeast strains (which primarily originate from Belgian breweries) will produce different and unique beers since these yeasts tend to be very ‘expressive’ in making varying types and amounts of esters and phenols (i.e., “Belgiany’ flavors). As regards beer styles of American Pale Ales and American style IPAs, the majority of US craft breweries utilize a neutral yeast for these beer styles. The concept is to showcase the hops in these beers and have very little flavor contribution in these particular beer styles. The yeast commonly used for these beer styles if California Ale yeast strain (Wyeast 1056, White Labs 001, US-05). Cheers!
This is great info, and confirms my idea about a "neutral" yeast (which I wasn't sure about). Thanks! What I'd like to see brewers do (some do it now, but far from all) is to list on the label of every beer they produce the specific yeast strain or strains used. Maybe I really like the yeast attributes of Duvel, for example. So I'd want to know what other beers use the same or similar yeast. They already do this for hop and malt varieties, so the next logical step is to include the yeast info too. (All of this said w/ the understanding that some or most breweries have a "house" yeast strain, which is often obvious from trying several beers from the same brewery.) Cheers!
One thing to note is that every breweries yeast strain will be distinctive to that brewery and that environment. Let's say I go out and buy a pouch of Wyeast 1272. I harvest the yeast from the first batch and freeze it down. I make a dynamite IPA that everyone loves, and I reuse the same yeast and the same strain over and over again in my IPA. Over time, this yeast, which started as 1272, will slightly mutate to my brewing environment; that is to say, the specific malt sugars in my wort, the temperature in my fermentation, the chemistry of my water, etc. It will therefore kick out different esters and other byproducts than it used to. And it will slowly - but surely - taste a bit different than it did initially. Which is why it doesn't really make sense for a brewery to name specific strains; after a while, every brewery really owns their own strain, which is slightly different than everyone else's. Make sense?
This thread is an example of why I belong to Beer Advocate. I just learned more about beer in 20 minutes than I learned in the past 5 years. Good post.
You also have generation loss with many types of yeast. Undesirable mutations that could kill your strain after a finite number of replications. I used to experience this quite a bit in the lab. We'd have a distinct number of reproduction cycles that affected our yeast strains. The fewer the better, for our uses. I'd be interested to hear how some of the really old breweries address this - more specifically, how they store yeast long-term to avoid the undesirable mutations over time.
Many breweries use yeast strains that are unique to them and are not otherwise commercially available and are a protected piece of info they will not share with other brewers. Thus they won't always want to tell you what they used. A fun experiment I have been able to sample is homebrewers who split a batch of beer and use 2 or more yeast strains on the same wort. It is really eye opening to see (and taste) how much difference the yeast strain can make when starting from exactly the same place. A couple years ago, the AHA (American Homebrewers Assosication) had a rally at Surly and the kind folks at Surly gave away unfermented wort to all the members who attended and had a sterilized carboy ready. They they asked that they all ferment that wort however they want but bring it back to the AHA National Convention later that year. I tasted a bunch of those beers and you would have never known they were the same except for the yeast (though fermentation temp and other variables will have and effect too) There are articles online about hombrewers who have split batches and done experiments with pitching different yeasts you can probably find it you search.
