Wyeast Roselaire First timer question

[brewinhard]

The Wyeast Brett L. is nice to work with for 100% brett beers and for secondary finishing. It gives the beer a nice, slightly tart cherry pie aroma and flavor. Wyeast lacto is pretty good too, though I have heard that the WL strain of lacto will actually produce alcohol that the WY version does not do.

[spiderwrangler]

though I have heard that the WL strain of lacto will actually produce alcohol that the WY version does not do.

Wondering where you heard this... It doesn't make sense to me, as the production of lactic acid and the production of alcohol are the two possible outcomes of fermentation pathways. I'm not aware of any organism that uses both pathways... Basically the breakdown of a glucose molecule (6 carbon) gives you 2 pyruvate molecules (3 carbon). In order to regenerate intermediate molecules needed to break down more glucose to produce energy, protons and electrons will get dumped back on to the pyruvate molecules. If it is done directly, it generates 3 carbon lactic acid molecules, as in us and lacto bacteria. If the 3 carbon pyruvate has a molecule of CO2 split off first before the protons and electrons are added to the remaining 2 carbon molecule, it produces ethanol.

If it isn't producing CO2, it isn't producing ethanol. That being said, there may be yeast present that are.

[brewinhard]

Good question... I am trying to think where I did read/hear that. Maybe over on the Babble belt where someone had emailed white labs about it and got that response. I will have to check and see if I can find that!

[BrewerJ]

Depends if it heterofermentative lactobacilli which can produce either alcohol or lactic acid from sugars and homofermentive only produce lactic acid. I used to have an email from wyeast explaining the difference between the two but I can not find it. I think the wyeast lacto is heterofermentive and the lacto in their berliner blend is homofermentive. I am not sure if white labs uses the hetero or homo. Both work well i feel that the wyeast is a little more aggressive than the white labs.

[spiderwrangler]

Depends if it heterofermentative lactobacilli which can produce either alcohol or lactic acid from sugars and homofermentive only produce lactic acid.

Huh, well, you learn something new every day. https://people.ok.ubc.ca/neggers/Chem422A/BIOCHEMISTRY%20OF%20LACTIC%20ACID%20BACTERIA.pdf

[brewinhard]

Well done Spider! Not that I would be able to fully explain that, but at least it helps to shed some light on the differences.

[Cody]

Good question... I am trying to think where I did read/hear that. Maybe over on the Babble belt where someone had emailed white labs about it and got that response. I will have to check and see if I can find that!

You did read/hear that on BBB. I am the one who emailed White Labs about their lacto, and yes, it does produce ethanol and lactic acid.

[spiderwrangler]

I am the one who emailed White Labs about their lacto, and yes, it does produce ethanol and lactic acid.

Do you know if it is half and half (one molecule of each for each glucose), or some other ratio?