Thursday, March 7, 2013

Evaluating Yeast Character, part II

Back in December, I started off my new yeast graphs by posting three of the cleanest and most neutral English yeasts that are commonly used by homebrewers. They were, Nottingham, Wyeast British Ale/Whitbread, and WhiteLabs Essex Ale. This time around, I'll discuss three more yeasts that are still considered relatively clean and neutral in flavor, although they do have more character than the previous selection. They are, Wyeast English Special Bitter, British Ale II, and WhiteLabs Bedford Bitter.

Although currently out of production, Wyeast English Special Bitter (1768) is among my favorite English yeasts for bitters and other hop and malt forward beers. Believed to be the Youngs yeast, this strain produces exceptionally clear and clean tasting beers with light fruity esters and a soft malt character that does well with high hopping. Although said to be the 'little brother' of the popular Fullers yeast, expect this yeast to produce far less fruity esters and not much in the way of diacetyl. It does flocculate nearly as well as the Fullers yeast and will produce exceptionally clear beer without need of filtration. However, this can cause problems as the yeast tends to flocculate out before fermentation is complete, leaving the beer with a high final gravity. It is also one of the fastest fermenting English yeasts I've come across.

Moreover, like the Fullers yeast, Wy1768 produces little in the way of a krausen and is not ideal for top cropping or open fermentation. I've had my best results with this yeast when fermented at a low temperature (62-65F), as it can produce some 'boozy' aromas when fermented warm. Lastly, if bottle conditioning, be absolutely sure the beer has reached its terminal gravity before bottling, lest you reactivate the yeast in the bottle and end up with gushers. Ideal beer styles include: Bitter, ESB, Nut Brown, English IPA. Similar yeast: ~ Wy1098.
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Supposedly the Adnams yeast (although the real thing is a dual strain), Wyeast 1335 produces clean and malty beer with some light fruit character. I've used this yeast a handful of times in the past and my overall impression has largely been somewhat mixed. On one hand it is a strong fermentor and an excellent top cropper, but it is also a relatively slow flocculator and it takes some time for the powdery yeast to fully settle. Yet, when it does settle out, it makes for a very clear beer. Regarding flavor, this yeast is quite neutral and does well in highlighting hop and malt character. It does produce some bready malt flavors and tartness - which I am largely not a fan of - and seems best used in beers where you want the yeast to play a secondary role. It has a clean and crisp finish.

Fermentation wise, the general consensus is that this yeast ferments well at low temperatures (mine were all at 62-65F) and it will produce some apple/pear/peachy esters at higher temps. I have a few home brewering friends who use 1335 as their "house yeast" as it is easily topcropped and is largely clean tasting. It is a bit too neutral my liking (especially for bitters), but I can say it makes a very nice American/English IPA and American Pale Ale. Ideal beer styles include: IPA, APA, Golden Ales, yeast-neutral Brown Ale, Robust Porter, and Stout. Similar yeast: ~ WLP 022, Wyeast 1056.
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There isn't much I can say about the Bedford Bitter yeast that I haven't said before. Certainly one of the more unique English yeasts available (although only for a few months a year), this yeast is bar-none my favorite yeast for English style bitters. When fermented properly, this yeast produces wonderfully balanced beer with a great mix of light stone-fruit esters and just the faintest hint of diacetyl, which can add richness and/or complexity in very small amounts. This yeast largely lets the hop and malt character of the beer shine, although I must admit I think it does better in hoppier beers than purely malty ones. What I like most about this yeast, is that it has a level of balance that other English yeasts often lack, in that it adds just enough of its own character to the beer without covering up the other ingredients.
                                                            
Fermentation wise, this yeast is one of the more difficult yeasts to handle - right up there with Ringwood - as is is noted to produce a slightly sulfury, sweaty, dirty sock type aroma when fermenting and some of that character can be carried over into the keg or bottle if you are not careful. Like using lager yeasts, you need to give this yeast ample time to let the sweaty aromas dissipate, especially if bottling. I have not experienced nearly the same degree of funky aromas with this yeast as some people have, although it is something to watch out for. For me (kegging) all vestiges of this aroma usually dissipate after a week in the keg, especially when flushed with c02 a few times.

Additionally, the Bedford yeast is a strong fermentor and typically reaches its FG within a weeks time. It flocculates well, but the yeast is powdery and it can be roused back into suspension easily. Given time and/or cold treatment, beers with this yeast can achieve a high level of clarity without the need of finings. Lastly, this yeast ferments better with a large pitch and higher levels of oxygenation. If possible use pure 02 and a stone, otherwise be sure to aerate well. I like to pitch this yeast low, 62-63F, hold the bulk of fermentation at 65F before free rising to 68F and then cold crashing. Ideal beer styles include: Bitter, ESB, English IPA, Golden Ale, American Amber/Pale Ale. Similar yeast: Hard to say... mix of Wyeast 1968 and 1335.

Next time.... Wyeast 1028, 1275, 1882, 1187.

Part I - Here

7 comments:

  1. Will, all very interesting and I found in particular your comments about sulphury notes in the Bedford even more so. Burton beers were said to have a sulfate ion note and they did IMO, as Marston's beer still does. (I don't get it really in the Bass as brewed domestically although it is an interesting beer and gains value IMO from the freshness of local production).

    I don't know if you caught up with the New Albion recreation. I get pronounced sulphury notes in that and think it must be the yeast. Perhaps back in '76 Jack McAuliffe was emulating Worthington White Shield for example.

    Final thought: the sulphur thing in my experience is even more common amongst lagers. Not Urquell, but many descendants from that especially some reputed German brands and kellers.

    Gary

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    1. I'm not familiar with the New Albion beer, although I have read a number of souces that mention a sulfury aroma in the Burton brewed ales. I always assummed it was due to high sulfate in their water, but yeast very likely does play a role. Been a while since I've had a fresh bottle of Worthington... or Bass for that matter.

      Also, it is interesting that the Bedford yeast was once a top cropper and now is (definately) not. I wonder if the sulfur note it produces has anything to do with the change from topcropping to bottom-harvesting. Like some Hefeweizen yeasts, they can produce quite a bit of sulfur when fermented too cold. Lastly, the WL Southern German Lager is a sulfur producing beast. Never had a lager yeast produce so much of the stuff...

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  2. I'd just like to add my voice to others thanking you for your efforts with characterising and allowing some form of comparison between yeasts here. This is great stuff and a really useful resource for brewers looking to match strains with brew types and preferred ester profiles etc.
    Especially useful is your info on the interactions with malt and hops as well as the ferment temps you use. To add a little detail - do you use a standard pitch rate, starter prep process for these English ale yeasts? If so what is it so we can have a crack at reproducing the effects you get.
    Cheers
    Mark

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    1. Thanks Mark. The graphs are far from perfect, but I figure they make for a decent starting point. As always, individual results may vary. :)

      For starters and wort oxygentation, I use the Mr. Malty yeast calculator, a stir plate, and pure 02. If I am repitching a small quantity of yeast - say old yeast or washed - I'll start with a smaller starter and step it up. Generally speaking, it is better to keep the amount of yeast proportional to the amount of starter wort so you aren't stressing the yeast and allowing for a lot of bacterial growth. For starters, 36hrs on the stirplate is plenty of time and for wort oxygentation I aim for 10-12ppm, which is about 60 seconds with an airstone. I almost always decant the starter before pitching and try to ensure the yeast temp is nearly the same as the wort I am pitching in to. You can kill a lot of yeast by pitching a cold yeast starter into warm wort, and vice versa.

      Hope that helps,

      Cheers

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  3. Thats great - thanks Will. Keep 'em coming (the beers and reviews that is!).
    Cheers
    Mark

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  4. I really enjoyed this and the other posts about evaluating yeast character. Do you have a follow-up in the pipeline?

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    1. There is a lot more I'd like to include on the subject - I have some really neat findings, complete with lab analysis - but alas... where to find the time. More to come...

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