Thirteen mini-ferments on the go! |
This is going to be a fairly extensive post, so here is the brief summary. As per usual, the meat is below the fold:
I selected about half of the 25 strains of yeast I isolated as part of my first wild yeast hunt, and grew up 1ml mini-starters, using 1.040 wort (no hops) and a shaker set at 32C. These 'starters' were then stored in a fridge for a few days until I could brew the Droit du seigneur Blonde; a low-hop (17IBU), modest-gravity (1.044) ale. I brewed an extra 5L of this beer, in order to give enough volume to setup 13 100ml mini-ferments, which were inoculated with the mini-starters. A month later I ran a flavour testing series, to see what these wild yeasts had produced. A month may seem like a long time, but since wild yeasts can sometimes be slow, a month gives a long enough ferment for even the slowest of yeasts to ferment to completion.
I did not get any particularly stellar yeasts out of this - about half were oxidative yeasts and barely reduced the gravity of the beer. I was more successful than I had expected - finding four strains with potential. But what really came out of this project is a usable method. SWMBO'd has a garden full of veggies right now all of them covered in local wild yeast!
All the nitty gritty below the fold.
Picking Strains:
Starters, ready to pitch. |
Yeasts are temporarily named by date, colony type (day 4 only) and their isolation number. I.E. D04SM-1 = day 4, small mucoid, colony #1. D10-3 is day 10, colony 3. I'll give real names to anything good.
Tasting Notes:
For each strain I am noting the bottle appearance,appearance in the sample glass, aroma, taste, final gravity (FG) of the wort, apparent attenuation (Ap. Atten.), and notes on anything else of interest. All samples - including the 'control' glass of Droit du seigneur Blonde (fermented with the very neutral US-05) are being drunk warm (room temperature) and uncarbonated. This brings out the taste of the sample - which, as you'll soon see - is not always a good thing!Interesting yeasts are highlighted in yellow, otherwise "notable" ones are highlighted in blue.
ID #
|
Appearance
|
Aroma
|
Taste
|
FG
|
Ap. Atten.
|
Notes:
|
|
Bottle
|
Glass
|
||||||
US-05 | NA (Kegged) | Clear, straw coloured. | Mild, fruity esters | Neutral, modest bitterness. | 1.010 |
76%
|
Control Beer, fermented with US-05. A nice, refreshing beer |
D04SM1 | Cotton-ball like yeast cake | Modest hazy | Bread-yeast like | Very fruity sweet | 1.036 | 18% | |
D04MP1 | Floating pellicle | Hazy, some yeast chunks | Cider | Dry, bland | 1.005 | 89% | High attenuation, but bland and boring - stale tasting |
D04LM1 | Chunky throughout brew | Snot-like consistency | Fungal | None | -- | -- | Thick like snot, couldn't measure FG. No taste (and yes, I tasted it) |
D10-1 | Thick yeast cake | Cloudy | Solvent-like, sweet | Sweet & lactic | 1.037 | 16% | |
D10-3 | Clear, easily disturbed yeast cake | Mild cloudiness | Bread yeast and cider | Ale-like, estery | 1.022 | 50% | May work as a co-fermenter; not ideal for solo ferments |
D20-1 | Fluffy yeast-cake | Highly cloudy | Unpleasant, fungal | sour/estery | 1.036 | 18% | Minimal ferment, surprisingly not bad taste. |
D20-3 | Lumpy but firm yeast cake | Mild cloudiness | Minimal, yeasty | Sweet, otherwise mild | 1.037 | 16% | |
D30-1 | Compact cake | Mild cloudiness | Fruity esters | Dry, astringent, bitter | 1.002 | 95% | Highly attenuation, but unpleasant. May work as a co-fermenter with ageing. |
D30-2 | Cloudy | Highly cloudy | Mild & neutral | Sweet, neutral | 1.038 | 14% | |
D30-3 | Cotton-ball yeast cake | Heavy cloudy | Slight acetone note | Sweet, neutral | 1.035 | 20% | |
D30-4T | Thin cake | Cloudy | Yeast & medicinal (phenolic) | Mouldy/mousy | 1.036 | 18% | Tastes like Bret, but was minimally fermentative. |
D30-5T | Cotton-ball yeast cake | Mild cloudiness | Mouldy | Sickingly sweet, horrendous flavour notes | 1.040 | 9% | Nasty, flavour outside of what I can find words for. |
D30-6T | Cake on bottom, heavy ring around top | Mild cloudiness, oily surface | Yeast & cider | Dry, estey, band-aid like phenols | 1.005 | 89% | Possibly Brett, may work well with long ageing |
Final Notes:
Out of the 13 strains that were tested, 1 was unpalatable the point of being nauseating, 1 turned the beer into snot, 7 were poor fermenters or otherwise boring, 2 may be usable in mixed fermentations, and 2 may work as a solo fermenters - assuming their more unpleasant characters fade with age. As success rates go, I think that's pretty good. Given the results I will continue tests with four strains, including attempting a DNA-sequencing based identification. Without further ado, let me introduce the strains worth further exploration:Potential Fermentative Strains:
These are strains which are sufficiently attenuating to be used as the sole organisms in a brew.
- D30-6T: Medicinal phenolics, esters and highly attenuating. Ma be Brettanomyces.
- D30-1: Lots of fruity esters, attenuates strongly but produces an astringent finish.
Potential Mixed Fermentation Strains
These are strains with interesting taste profiles, but which lack the attenuation to be used as the sole strain in a fermentation.
- D10-3: Ale-like esters, but minimal attenuation. May work as a co-fermenter, but its hard to conceive of a place where it could be used in place of a real ale yeast.
- D20-1: Produces a ferment with fruity esters and a bit of a lactic twinge. Surprisingly enjoyable, but has an unpleasant aroma. Weak attenuation means this strain needs to be used in a mixed ferment
Interesting results from your hunt. Keep up the good work.
ReplyDeleteVery cool stuff. You're brave, tasting some of those!
ReplyDelete