Is Safale s-04 REALLY kill-factor neutral?

[lumberjackjack]

Greetings all!

I was hoping to hear from someone who can confirm that Safale s-04 is indeed kill-factor neutral. I have been told by two agents from Safale that it is, but I find this hard to believe; no other ale yeast with the characteristics of S-04 is kill-factor neutral.

Thanks!

 

[VikeMan]

no other ale yeast with the characteristics of S-04 is kill-factor neutral.

What characteristics are those?

 

[lumberjackjack]

POF negative and neutral flavor.

 

[VikeMan]

POF negative and neutral flavor.

What's the connection between those things and killer/neutral/sensitive? Almost all ale strains are sensitive, regardless of those two characteristics.

 

[lumberjackjack]

A kill-factor neutral ale yeast could be used together with killer wine yeast strains.

 

[VikeMan]

A kill-factor neutral ale yeast could be used together with killer wine yeast strains.

Yes, it could. But I still don't understand why you doubt Safale's claim of S-04 being neutral.

Anyway, if in doubt, why not do a little test batch (a quart of DME wort would do) with a 50/50 mix of S-04 and your favorite killer wine strain? If you get S-04-like attenuation, it's probably neutral. If you get a terribly under-attenuated beer, it's probably sensitive.

 

[lumberjackjack]

I doubt their claim because it seems unlikely that they would have the only kill-factor neutral ale yeast that is POF negative with a neutral flavor profile.

That sounds like a good test idea that is simpler than I had in mind, thanks! I was hoping though to hear from someone who has played around with this and could tell me yay or nay.

 

[lumberjackjack]

Update: A 2-gallon batch fermented with EC-1118 was successfully restarted with Safale S-04. This could mean that S-04 is indeed kill factor neutral and/or could indicate that the kill factor protein released by EC-1118 is less active or even inactive post primary.

In this batch S-04 is feeding on the more complex malt sugars only, which I am hoping will have a discernable impact on the final brew...and hopefully a positive one.