Author Topic: Help! Master thesis about wild yeast  (Read 858 times)

Offline christine87

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Help! Master thesis about wild yeast
« on: February 08, 2017, 11:53:23 AM »
Hi guys!

I'm writing a mastes thesis on wild yeast isolated from spontanious fermented cider (10 celsius or 20 celcius) and a plant called "kveke" in norwegian used in spontanious fermented beer on local farms for centuries.
I am also using two other yeast strains; WLP 6788 Norwegian Farmhouse Ale, and one I choose myself. I am then analyzing the differnces in the brew caused by the yeast. (Sensoric, aromatic compounds, ect.)

I am using the same wart in all the four brews, but I need help to find one that is likely to taste good- without  drowning the differences in taste originating from the different yeast strains. (So perhaps not a lot of hop-flavour).
I've thought about a type of blonde or saison, but I'm no expert..

I've gotten this suggestion from my professor:

Recipe: (malt, hops after choice):
3,5 kg pale-ale
0,2 kg light crystal
0,3 kg wheat malt

Any thoughts or ideas? :)

Offline reverseapachemaster

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Re: Help! Master thesis about wild yeast
« Reply #1 on: February 08, 2017, 04:34:43 PM »
It's a matter of what question you intend to answer in your thesis. If your goal is only to evaluate the yeast in a broad sense then the recipe below is fine. You'll want to add hops for bittering somewhere in the 10-20 IBU range.
Heck yeah I blog about homebrewing: Brain Sparging on Brewing

Offline bayareabrewer

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Re: Help! Master thesis about wild yeast
« Reply #2 on: February 08, 2017, 04:51:28 PM »
Your question is about wort production and producing one that is consistent and lightly flavored enough to see the different types of yeasts expressions? If that's the case, perhaps extract is a better option. You will be guaranteed to have the exact starting gravity and wort fermentability for every trial.

Offline erockrph

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Re: Help! Master thesis about wild yeast
« Reply #3 on: February 09, 2017, 08:58:02 PM »
Your question is about wort production and producing one that is consistent and lightly flavored enough to see the different types of yeasts expressions? If that's the case, perhaps extract is a better option. You will be guaranteed to have the exact starting gravity and wort fermentability for every trial.

I agree - extract is an excellent starting choice if you want a rather neutral, but consistant starting point. I use 80% Pilsner DME or Extra Light DME and 20% Munich LME for my base recipe when trialing new hop varieties. The Munich LME gives just enough maltiness that the beer doesn't taste too plain, and enough of a backbone to see how the hops interact with the malt. I would expect a similar recipe to work well for a yeast trial.
Eric B.

Finally got around to starting a homebrewing blog: The Hop Whisperer

Offline christine87

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Re: Help! Master thesis about wild yeast
« Reply #4 on: February 13, 2017, 01:02:03 PM »
Your question is about wort production and producing one that is consistent and lightly flavored enough to see the different types of yeasts expressions? If that's the case, perhaps extract is a better option. You will be guaranteed to have the exact starting gravity and wort fermentability for every trial.

I agree - extract is an excellent starting choice if you want a rather neutral, but consistant starting point. I use 80% Pilsner DME or Extra Light DME and 20% Munich LME for my base recipe when trialing new hop varieties. The Munich LME gives just enough maltiness that the beer doesn't taste too plain, and enough of a backbone to see how the hops interact with the malt. I would expect a similar recipe to work well for a yeast trial.

Thanks for the feedback!

The point is to look at the difference in aromatic compounds, organic acids etc. that derives from the yeast metabolism, and how it affects the flavor and quality of the end product.
At my university we have a micro brewery big enough to make a batch that can be used for all four strains of yeast and the batches therefore won't differ in any other way than the yeast.

I am going to extract wild yeast from spontaniously fermented cider, and therefore also wonder if anyone has tried this before?

Offline dmtaylor

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Re: Help! Master thesis about wild yeast
« Reply #5 on: February 13, 2017, 02:19:56 PM »
I am going to extract wild yeast from spontaniously fermented cider, and therefore also wonder if anyone has tried this before?

I have made spontaneously fermented cider, but never transferred it subsequently into a beer wort as you intend to do.  This should make for an interesting experiment/thesis.  I wouldn't even know what to expect from wild cider yeast in beer.

One thing I would like to point out: At least in cider, I find the flavors (and chemical constituents) to evolve significantly over time, so you should be very specific about the timing of your analyses, as well as temperatures, etc.  You may wish to conduct analyses at many phases on a frequency such as weekly or biweekly, and note the changes over time.  After several months, the changes should level off, but I'd be curious in a comparison of results at say 2 weeks versus 6 months or something like that.  I bet there are huge differences in flavors and chemical constituents from early fermentation compared to completion.
Dave

The world will become a much more pleasant place to live when each and every one of us realizes that we are all idiots.

Offline bayareabrewer

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Re: Help! Master thesis about wild yeast
« Reply #6 on: February 13, 2017, 02:50:45 PM »
Your question is about wort production and producing one that is consistent and lightly flavored enough to see the different types of yeasts expressions? If that's the case, perhaps extract is a better option. You will be guaranteed to have the exact starting gravity and wort fermentability for every trial.

I agree - extract is an excellent starting choice if you want a rather neutral, but consistant starting point. I use 80% Pilsner DME or Extra Light DME and 20% Munich LME for my base recipe when trialing new hop varieties. The Munich LME gives just enough maltiness that the beer doesn't taste too plain, and enough of a backbone to see how the hops interact with the malt. I would expect a similar recipe to work well for a yeast trial.

Thanks for the feedback!

The point is to look at the difference in aromatic compounds, organic acids etc. that derives from the yeast metabolism, and how it affects the flavor and quality of the end product.
At my university we have a micro brewery big enough to make a batch that can be used for all four strains of yeast and the batches therefore won't differ in any other way than the yeast.

I am going to extract wild yeast from spontaniously fermented cider, and therefore also wonder if anyone has tried this before?

I have, albeit not with cider. My friend owns a ranch with a ton of peach and pear trees. I make a small half gallon fruit starter that ferments with whatever yeasts and what not are on the skins then I incrementally feed it wort for a month or so. I use this wild starter to make ten gallons of a wheat beer that ages for a year and gets fruit from the next harvest. I recently isolated a saccharomyces type yeast from the beer that I'm going to begin experimenting with. My past experience with wild sacch is that it is usually hyper attenuative, settles out poorly and tastes very phenolic and spicy.

Offline erockrph

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Re: Help! Master thesis about wild yeast
« Reply #7 on: February 13, 2017, 03:48:40 PM »
Your question is about wort production and producing one that is consistent and lightly flavored enough to see the different types of yeasts expressions? If that's the case, perhaps extract is a better option. You will be guaranteed to have the exact starting gravity and wort fermentability for every trial.

I agree - extract is an excellent starting choice if you want a rather neutral, but consistant starting point. I use 80% Pilsner DME or Extra Light DME and 20% Munich LME for my base recipe when trialing new hop varieties. The Munich LME gives just enough maltiness that the beer doesn't taste too plain, and enough of a backbone to see how the hops interact with the malt. I would expect a similar recipe to work well for a yeast trial.

Thanks for the feedback!

The point is to look at the difference in aromatic compounds, organic acids etc. that derives from the yeast metabolism, and how it affects the flavor and quality of the end product.
At my university we have a micro brewery big enough to make a batch that can be used for all four strains of yeast and the batches therefore won't differ in any other way than the yeast.

I am going to extract wild yeast from spontaniously fermented cider, and therefore also wonder if anyone has tried this before?

I have, albeit not with cider. My friend owns a ranch with a ton of peach and pear trees. I make a small half gallon fruit starter that ferments with whatever yeasts and what not are on the skins then I incrementally feed it wort for a month or so. I use this wild starter to make ten gallons of a wheat beer that ages for a year and gets fruit from the next harvest. I recently isolated a saccharomyces type yeast from the beer that I'm going to begin experimenting with. My past experience with wild sacch is that it is usually hyper attenuative, settles out poorly and tastes very phenolic and spicy.
Interesting. I've been meaning to grow up a culture from some of my berries, but haven't gotten around to it yet. I've heard that wild Sacc is often underattenuative, because it hasn't evolved to ferment maltotriose and/or other more complex sugars. Guess that's not always the case...
Eric B.

Finally got around to starting a homebrewing blog: The Hop Whisperer

Offline bayareabrewer

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Re: Help! Master thesis about wild yeast
« Reply #8 on: February 13, 2017, 04:21:22 PM »
underattenuation, hasn't been my experience at all. The culture ferments worts down to 1.004-1.002 regardless of mashing in under a week. I think my method of growing the starter helps. The initial fermentation of the fruit smells awful-sulfur, smoky, bandaids, pretty much everything you don't want. My idea behind the incremental feedings of wort is to help acclimate the yeast to wort and also let the wild yeast eventually out compete all the other stuff. Its quite unscientific but its served me well.

With my isolate culture I'm gonna start playing around trying to select for flocculation and see what effect that has on attenuation as well.