Adding boiled yeast?

[Tiwas]

According to http://www.gotmead.com/forum/showthread.php?t=10631 boiled yeast should be added to the end of the ferment of show-meads. I guess mine's pretty close, so...should I boil up some bread yeast and add to the must? If so, how much?

Cheers!

 

[Medsen Fey]

Well give us the details, and we may be able to give you some better suggestions.

 

[Tiwas]

The one I have in the brewlog section (http://www.gotmead.com/forum/showthread.php?t=17611) is getting close now (~1.012 last night) and is *reeeeeally* slowing down.

This is the section I was referring to:

6. Yeast is yeast, dead or alive, add some killed off yeast cells when your ferment slows down. When your ferment starts to slow it's time to add some yeast into your must, dead yeast that is. You may boil your own yeast to kill them off and then decant the supernate once it has cooled and stir in the dead yeast/ghosts slowly. The inactivated yeast cell walls adsorb adsorb medium-chain fatty acids that are toxic to yeast, they also provide nucleation sites to help keep the yeast in suspension. Highly clarified honey musts (generally resultant from using light and filtered honey) will allow the yeast to drop out of suspension more readily, this is why it is important to use a raw unfiltered dark colored honeys in my opinion.

 

[mccann51]

Hopefully I remember this correctly, but a tsp (~4-5g) will provide ~25ppm YAN in a gallon, so depending on how much nutrient you want, take it from there.

 

[wayneb]

This late in fermentation you are not adding the yeast primarily for YAN, but more for the hulls' ability to remove yeast toxins so that the remaining active yeast can ferment to completion. Any YAN that comes along will probably get mostly used by the active yeast, provided you don't overdose severely.

For this purpose, the typical dose of commercially prepared yeast hulls is on the order of a tenth to one half gram per gallon. If you add much more than that you can contribute yeasty aromas and tastes to the must. I honestly have no idea how much of the hulls results from Oskaar's boil and decant approach, but I would not think that you'd go wrong with about a gram of dry yeast, boiled and with supernate decanted off per Oskaar's directions, per gallon of your must.

But before you do this, ask yourself an important question: Is this a sluggish fermentation likely to stick at a gravity higher than I want it to finish? If so, then the hulls are useful to try to prevent that. If not, then the addition is unnecessary.

 

[Medsen Fey]

You gave that batch nutrients at the beginning, so right now, you may benefit from some yeast hulls to bind potential toxins. About 0.5-1 gram per gallon of yeast hulls would be plenty. If you want to use boiled yeast, I'd probably go with 2 grams per gallon as you'll be getting more than just the hulls.

Edit- I see Wayne is fast on the draw today!

 

[wayneb]

And I see that I'm more conservative in my dosing than you are! Well, your dose shouldn't cause too many yeasty taste issues, but I always like to err on the side of "less is better" when I do late additions of anything.

 

[Soyala_Amaya]

OK, I checked the glossary...what the heck does "decant the supernate" mean? And how much water do you boil your (for a 5 gallon must) 2.5 grams yeast in?

 

[Tiwas]

But before you do this, ask yourself an important question: Is this a sluggish fermentation likely to stick at a gravity higher than I want it to finish? If so, then the hulls are useful to try to prevent that. If not, then the addition is unnecessary.

If it stops at 1.010, I wouldn't mind. I like sweet mead, so only "problem" would be less alcohol in it

You gave that batch nutrients at the beginning, so right now, you may benefit from some yeast hulls to bind potential toxins. About 0.5-1 gram per gallon of yeast hulls would be plenty. If you want to use boiled yeast, I'd probably go with 2 grams per gallon as you'll be getting more than just the hulls.

Edit- I see Wayne is fast on the draw today!

And I see that I'm more conservative in my dosing than you are! Well, your dose shouldn't cause too many yeasty taste issues, but I always like to err on the side of "less is better" when I do late additions of anything.

How about boiling 1g normal baking yeast per gallon? I think the cubes they come in are like 5g, so I wouldn't even have to break out my very inaccurate scale...

OK, I checked the glossary...what the heck does "decant the supernate" mean? And how much water do you boil your (for a 5 gallon must) 2.5 grams yeast in?

I'd like to know, too. Guess it means let the dead yeast fall to the bottom and remove the water or something...?...

 

[wayneb]

"Decant the supernate" is Oskaar's way of showing off his breadth of biochemical engineering knowledge! ;D It means "pour off the liquid at the top."

And yes, one g of baking yeast cake (the refrigerated "wet cake" - interesting that you can still get yeast that way there. Here in the US, it is almost impossible to find in a wet cake any more) is approximately equivalent to 1/2 g of active dry yeast.

Finally, I would use enough water that the yeast stays completely wet through the process, and that there is liquid enough to actually pour off after the boil. I'd use on the order of 50 ml per 5 g of yeast, minimum. More won't hurt.

 

[Tiwas]

Thanks! Might as well just boil it in half a liter or something, then. At least it won't boil dry

I'm off to the shop tomorrow! Hopefully, I won't have to settle for dry yeast, but I know we could get that cube the last time I baked a cake (which means it very well could be discontinued by now )