A guide to making FF cultures

[Pumilo]

Originally Posted by Brotherly Monkey

I was speaking with some guys at the local feed mill (only place to pick up peat, perlite, etc, in my area) and they hoooked me up with a small bag of game bird mash (I think a 50lb bag regularly retails for around 20-30 dollars) to try in my cultures.

Has anyone tried anything like this in the past? I figured I would try to cut my current media by a third, and see what happens. It's non medicated and 22% protein

Kind of like this? FF media recipes list

[Brotherly Monkey]

[RMB]

Originally Posted by TheUnseenHand

Can anyone enlighten me as to why Brewers Yeast is used over bakers yeast from the start? I honestly haven't looked at prices or anything, but is the Brewers Yeast cheaper? Or is it because it's powdered it allows for more even and thorough distribution in the mix? Or is it actually a different species of yeast that has a benefit that the bakers yeast doesn't?

If nobody's answered this yet,

Brewers yeast is the left over yeast that accumulates after fermentation is complete. Yeast cells multiply rapidly. Only a small package of yeast is needed to start a batch of beer, but it colonizes quickly, usually leaving a sludge of yummy yeast down in the bottom of your fermenter. At that time it is alive, but there's nothing left for it to consume. The beer is siphoned off the top, leaving the sludge behind.

It is a different strain of yeast, although using bakers yeast will work for beer, or beer yeast for wine, or brewers yeast for bread, it won't taste right or won't be able to live in the alchohol it produces, resulting in an incomplete fermentation. The brewers yeast that you buy as a food supplement though is dead dried yeast cells, and can't be used for baking or brewing, it's just the dried and milled up leftovers from some breweries vats, which doesn't explain why it's so expensive. It is however a good source of proteins and all kinds of nutrients, for you and your flies. Homebrewed beer is also a lot better for you because of the amount of yeast left in the bottle, the B vitamins actually help prevent hangovers. So even if I pour it into a glass so it looks pretty, I always drink the sediment on the bottom!

[tim13]

I heard a rumor that Easter grass works well for FF cultures. Since its on sale for a quarter a bag, thought I might try it out. Anyone else tried it?

[Ed]

Originally Posted by TheUnseenHand

Can anyone enlighten me as to why Brewers Yeast is used over bakers yeast from the start? I honestly haven't looked at prices or anything, but is the Brewers Yeast cheaper? Or is it because it's powdered it allows for more even and thorough distribution in the mix? Or is it actually a different species of yeast that has a benefit that the bakers yeast doesn't?

As you culture flies you will develop strains of yeast that are adapted to your media and culture methods. Those yeast are transferred by the flies and will outcompete the bakers yeast. The addition of the baker's yeast is for two reasons, the first is that it gets egg laying to occur more rapidly and the second is that it helps prevent unwanted microbes or fungi from colonizing the media.

The reason the brewer's or nutritional yeast is used is because it increases the protein content of the media and gives a controlled level of protein in the media. Adding live yeast doesn't give you the same control and if you add too much protein the production will go down.

Ed

[Reef_Haven]

Originally Posted by Ed

The reason the brewer's or nutritional yeast is used is because it increases the protein content of the media and gives a controlled level of protein in the media. Adding live yeast doesn't give you the same control and if you add too much protein the production will go down.

Ed

Ed,
What is an ideal % level of protein in the dry portion of media? and how much would be too much?
I've been using the Walmart Great Value brand of mashed potato mix. The box indicates 1 portion is 22g dry and of that 2g is protein, that works out to 9% protein.
To this I add 1/6 brewers yeast (~50% protein) and 1/6 powdered sugar.
If I am doing the math correctly, that works out to 13% protein.
Some of the analysis on fruit fly medias I have seen are only 5% protein or so.
There seems to be some disconnect there, what am I missing?
Thanks.

[Ed]

Anything over 5% isn't needed as it doesn't do anything for production..

Are you sure your brewer's yeast is 50% protien by weight? Most references have it listed as much less than that.. usually closer to 30%...? You also need to make sure that all of your protein content is based on the weight and not say by calories or RDA...


Ed

[Reef_Haven]

Originally Posted by Ed

Anything over 5% isn't needed as it doesn't do anything for production..

Are you sure your brewer's yeast is 50% protien by weight? Most references have it listed as much less than that.. usually closer to 30%...? You also need to make sure that all of your protein content is based on the weight and not say by calories or RDA...


Ed

Brewer's Yeast is 15g per serving protein is 7g so 46.6%, close to 50%.
http://www.puritan.com/brewers-568/b...2270?NewPage=1
It's the potato flakes that have me stumped. 9% protein seems high for dried potatoes. Still if I don't add brewers yeast, the yield is very low.
http://www.walmart.com/ip/Great-Valu...utrition+Facts
Thanks for helping me figure this out.

[Ed]

What is the total final dry weight of your media?

[Ed]

so you use 22 grams potato plus (0.17)(22) grams yeast plus (0.17)(22) grams sugar per culture?

this gives 22 plus (22)(0.17) plus (22)(0.17) = 22 plus 7.3 grams = 29.3 grams total.

The general amount of protien I get in the real literature (non-advertised) is between 32 and 46% so if we use 40% as the halfway point we get

total protien (Accepting your potato levels) is 2 plus (.4)(3.7)= 2 plus 1.5 = 3.5 grams protein. If your labels are correct then that is close to 11% total protien.

I think the potato label is right but are you sure you are using that weight of yeast and sugar to that weight of potato?