Thursday, 29 April 2010

19. Battle of the Yeasts

The 50 hop was racked into cask yesterday and I had my first taste of the Shellfish Stout in bottle. I am really pleased with both of them. The IPA, even after dry hopping, I fear will be slightly too reserved for the true hop disciple so I am doing another one with more hops in the boil. I think it is a wonderful drink but if I am to impress those who demand papillial erosion from their beer, it needs more nuts. I have got a 500ml pot of 30% iso alpha acid that a hop merchant gave me gathering dust in the lab that I could use but that would be cheating. The Shellfish Stout is superb, sublime and fantastic. You can really taste the shellfish. They give the beer a salty almost samphire-like character which works brilliantly with the generous hops and dry malt. It’s almost like you are drinking it on Padstow harbour on a November morning with your arm around Rick Stein. I wish that you could try some. I really do!

The first beer to go down to the effluent plant was only partially a 52 brew beer. The 12% red had “issues” in the fermenter and in the cask was carrying the early signs of wild yeast infection. It was also too sweet and just toilet all round. Serves me right for slipping it in, in the first place (as the actress said to the bishop). I bottled the Dark Saison a couple of weeks ago and have sent it to Lord ATJ, who suggested it as a brew, for a professional review. I really enjoyed it and it had my flavour panel searching for Jilly Goolden-style superlatives last Friday. I tried one of the bottles of Cardamom Wheat again last week and it still tastes like something Barry Scott would shout at you.

We are fast approaching the half way point in the journey of discovery that is 52 brews in a year. So far I have made stars of the hop (50 hop and DUSI) special malt (25-grain Chechen Imperial Porter), Herbs and Spices (Gruit Ale and Cardamom wheat), bacteria, shellfish and even animal organs (Heston’s Offal Ale). It is now time to turn to the Cinderella of brewing, Saccharomyces cerevisiae (brewer’s yeast).

I once read an article in the Brewer’s Guardian by a very well regarded brewing academic which basically said the yeast strain is largely incidental to beer character. At the time being newly graduated I took this as gospel and assumed that the brewhouse and process stages along with control of fermentation were where the true key to flavour control lay. Quite a few years on I can only assume that the eminent professor was talking about strain of yeast within a style of yeast because I have found the contribution of yeast to be absolutely pivotal to a number of defining beer attributes. If he wasn’t then he should have spent longer brewing and less time studying barley beta glucans.

At a few times in my career I have had run ins with yeast. Yeast can be a dream come true or a nightmare made reality. Once a few years back I was at a brewery, (name withheld), where the yeast just started to do stupid things. We looked at changing the yeast and got in samples of commercial yeast strains which had similar flavour characteristics. We did small scale trials on the same wort pitched with different yeast. All were significantly different from the brewery strain and each other. I was stunned at the degree of variation within a group of yeasts which were all described as top fermenting British ale yeast with a fruity and dry flavour. Fortunately the brewery in question’s yeast started behaving again.

Battle of the yeasts isn’t just about what flavours a yeast strain can produce, it’s also about how much and how quickly. I am creating an even field by ensure that the cell number, viability and condition of all the yeast are equal. The contribution of the yeast to the flavour will depend on which compounds it produces as well as how well it competes for nutrients in the wort. The yeast may be able to produce pronounced, characteristic aromas like bananas and cloves but if it is last to the oxygen and sugar feeding trough, it isn’t going to be able to ferment strongly enough to contribute to the overall flavour. Conversely Sharp’s yeast may compete well for the available nutrients but its naturally clean and gently fruity contribution may be drowned out by the more expressive Belgian and German yeast.

In the words of Harry Hill, there’s only one way to find out. FIGHT!!!!

10 comments:

Adrian Tierney-Jones said...

‘It’s almost like you are drinking it on Padstow harbour on a November morning with your arm around Rick Stein.’
What a wonderfully poetic and surreally comical vision — love it.

ZakAvery said...

Stuart, will fermentation temperature have any effect on the activity and dominance of the various yeast strains, or are they all fairly equal in that respect?

Stuart Howe said...

Zak hi,
Good question as always Mr Avery! You should be brewing beer. I am letting the yeast govern the fermentation temperature. They are all going into a semi insulated FV at 20C so the heat they produce will determine the fermentation temperature. The yeast are all ale strains so will cope equally well up to 25C above that and the Scourmont yeast could predominate.

Velky Al said...

This weekend I will be doing a side by side tasting of two versions of a lime and coriander infused witbier that make, called LimeLight 2. The original variant, 2.0, was fermented using Wyeast's Belgian Wit, and version 2.1 using Wyeast's Belgian Wheat. In all other aspects, the beers are exactly the same, so we will see the effect of the yeast I hope, quite clearly. Will post the results next week.

Crown Brewer Stu said...

fascinating stuff Stuart! I did a brew yesterday that might interest you, I will blog on my web site at more length. the short version is, I collected 3 brls of wort at 1063 and used it instead of water in a second mash. the we then got 3.5 brls at 1110 and boiled it for 90min with 2kg of summit 17.1%. we also got a small beer 3.5 brls at 1035.

Stuart Howe said...

Nice experiment Al. Wish I could taste the outcome. I love the Belgian Wit yeast personally. Really complex ester profile.

Stu, That wort sounds formidable. With the brutality of the Summit you should get a pretty good balance. Where are you going to find a yeast hard enough to cope with that? I assume you are oxygenating and pitching it to buggary?

beerevolution said...

Great post, young Stuart! We did some bottle conditioning trials a few years back with Jaipur and used half a dozen different yeast strains for the refermentation, then blind tasted. Incredible how even in refermentation the yeast altered the beer characteristics.

Kelly

haddonsman said...

First time I read this, I got as far as the word 'samphire' and then began to drool openly. Salty-hoppy just makes me want to up roots to the coast asap.

Second time round, I thought: finally. Someone with the balls to go all-out with yeast experimentation.

Third time round, I fetl slightly embarrassed that I've never read your blog before. Looks like I have a bank holiday weekend's worth of catching up to do.

Stuart Howe said...

Thanks Kelly. It's been a while (3 years)since anyone who has called me young so bless you. Jaipur with Saison yeast would be very very sexy.

Thank you Haddonsman. It's good to have you aboard!

Crown Brewer Stu said...

4 packets of US-05, checked it this morning and its going like stink!

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