Jaja, jeg skjønte at noe måtte være feil med kalkulatoren så jeg lagde en fire liter starter med fire stk tre måneder gamle rør, så da burde det holde, hehe. Man lærer stadig.
Oppbevaring av husgjær og pitching rate
- Trådstarter Frode T
- Startdato
Den gir ganske like svar som brewersfriend som jeg også har brukt, men der ligger vel linær modell inne. Uten mikroskop kan man lure seg blå. Har begynt å måle volum sediment for å kunne ha en referanse. Første ut er wlp001 der første runde ga en tetthet på 4,5B/ml sediment hvis kalkulatoren er riktig. Tenkte å sjekke etterhvert med serie-fortynning om dette stemmer. Da kan man bruke volum sediment som mål for hver stamme man har sjekket.
Tatt fra https://www.reddit.com/r/Homebrewing/comments/1x9sx3/how_to_estimate_yeast_cell_count/
YEAST COUNTING BY DILUTION
BACKGROUND
Visual estimation of cell density is based on the eye's fairly sharp threshold for observing turbidity. When viewed in a standard 13 x 100 mm tube, yeast suspensions of less than about 1,000,000 cells per ml are not visibly turbid. Above this threshold density they are visibly cloudy. By adjusting the number of cells in a suspension until just barely visible, you can obtain a suspension of known density (approximately 1,000,000 cells/ml) and then use the dilution factor to obtain the slurry concentration.
METHOD - BALLPARK CONCENTRATION
1) Take 1 mL of well-resuspended slurry, and add it to 9 mL water, mixing well. This is your 1:10 dilution.
2) Take 1 mL of 1:10 dilution, and add it to 9 mL water, mixing well. This is your 1:100 dilution.
3) You see where I am going with this... Just keep making dilutions until the suspension is not turbid. THIS is the dilution where you have ~1,000,000 cells/mL.
4) Calculate the cell density in slurry.
This step is easy.
cell density in slurry = (1,000,000 cells/mL) * (dilution factor)
Lets say the dilution you hit where the suspension is no longer cloudy is 1:100. That means:
cell density in slurry = (1,000,000 cells/mL) * (100) = 100,000,000 cells/mL
METHOD - ACCURATE CONCENTRATION
***** NOTE: If you have a turbid 1:10 dilution, and your 1:100 is not turbid, your ACTUAL point of no turbidity may be somewhere in between the two dilutions. To be most accurate, once the dilution is no longer visible (ex. 1:100), take the last turbid dilution (ex. 1:10) and do a 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8 and 1:9 dilution of that, in this case giving a total dilution of 1:20, 1:30 ,1:40, 1:50, 1:60, 1:70, 1:80 and 1:90, respectively. Let's say the dilution where there is no longer turbidity is the 1:4 dilution (1:40 total dilution).
Then:
cell density in slurry = (1,000,000 cells/mL) * (40) = 40,000,000 cells/mL
BIG DIFFERENCE!
Hope this helps you. It works great for me. I am pretty close every time. I work in a lab and I have checked my dilutions using a hemocytometer and a microscope. I am usually within ~10% of 1,000,000 cells/mL on my non-turbid dilution, but I have accurate graduated cylinders from work. I actually now use 10 mL volumetric flask and a 1 mL volumetric pipette. Haven't measured my accuracy and precision since the upgrade, but I can only assume it's gotten better. If you do this technique, invest a small amount of money (like $20) on a nice 10 mL graduated cylinder and ~20-30 13x100 mm test tubes (or some even more accurate volumetric flasks/pipettes, though those will be a little more expensive). The tubes and the graduated cylinder can both be washed and reused. ALSO, get a nice 100 mL graduated cylinder for measuring out the volume of slurry that you calculate you need for a given batch. Knowing the cell concentration within ~10% doesn't accomplish anything if, in the end, you don't have an accurate measurement of the volume of slurry you are adding.
Tatt fra https://www.reddit.com/r/Homebrewing/comments/1x9sx3/how_to_estimate_yeast_cell_count/
YEAST COUNTING BY DILUTION
BACKGROUND
Visual estimation of cell density is based on the eye's fairly sharp threshold for observing turbidity. When viewed in a standard 13 x 100 mm tube, yeast suspensions of less than about 1,000,000 cells per ml are not visibly turbid. Above this threshold density they are visibly cloudy. By adjusting the number of cells in a suspension until just barely visible, you can obtain a suspension of known density (approximately 1,000,000 cells/ml) and then use the dilution factor to obtain the slurry concentration.
METHOD - BALLPARK CONCENTRATION
1) Take 1 mL of well-resuspended slurry, and add it to 9 mL water, mixing well. This is your 1:10 dilution.
2) Take 1 mL of 1:10 dilution, and add it to 9 mL water, mixing well. This is your 1:100 dilution.
3) You see where I am going with this... Just keep making dilutions until the suspension is not turbid. THIS is the dilution where you have ~1,000,000 cells/mL.
4) Calculate the cell density in slurry.
This step is easy.
cell density in slurry = (1,000,000 cells/mL) * (dilution factor)
Lets say the dilution you hit where the suspension is no longer cloudy is 1:100. That means:
cell density in slurry = (1,000,000 cells/mL) * (100) = 100,000,000 cells/mL
METHOD - ACCURATE CONCENTRATION
***** NOTE: If you have a turbid 1:10 dilution, and your 1:100 is not turbid, your ACTUAL point of no turbidity may be somewhere in between the two dilutions. To be most accurate, once the dilution is no longer visible (ex. 1:100), take the last turbid dilution (ex. 1:10) and do a 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8 and 1:9 dilution of that, in this case giving a total dilution of 1:20, 1:30 ,1:40, 1:50, 1:60, 1:70, 1:80 and 1:90, respectively. Let's say the dilution where there is no longer turbidity is the 1:4 dilution (1:40 total dilution).
Then:
cell density in slurry = (1,000,000 cells/mL) * (40) = 40,000,000 cells/mL
BIG DIFFERENCE!
Hope this helps you. It works great for me. I am pretty close every time. I work in a lab and I have checked my dilutions using a hemocytometer and a microscope. I am usually within ~10% of 1,000,000 cells/mL on my non-turbid dilution, but I have accurate graduated cylinders from work. I actually now use 10 mL volumetric flask and a 1 mL volumetric pipette. Haven't measured my accuracy and precision since the upgrade, but I can only assume it's gotten better. If you do this technique, invest a small amount of money (like $20) on a nice 10 mL graduated cylinder and ~20-30 13x100 mm test tubes (or some even more accurate volumetric flasks/pipettes, though those will be a little more expensive). The tubes and the graduated cylinder can both be washed and reused. ALSO, get a nice 100 mL graduated cylinder for measuring out the volume of slurry that you calculate you need for a given batch. Knowing the cell concentration within ~10% doesn't accomplish anything if, in the end, you don't have an accurate measurement of the volume of slurry you are adding.
Ut i fra Woodland så får du 610 B fra ett av de rørene fra en 4l 10 plato starter 
. Du kan jo vurdere å dele den i det minste i to etter den er ferdig. Putt den i kjøleskapet og du har nok til et brygg til.
Synes det er litt rart at de fleste kalkulatorene ikke bruker infoen fra leverandørene om at halveringstiden er 120 eller 180 dager (purepitch).
. Du kan jo vurdere å dele den i det minste i to etter den er ferdig. Putt den i kjøleskapet og du har nok til et brygg til.Synes det er litt rart at de fleste kalkulatorene ikke bruker infoen fra leverandørene om at halveringstiden er 120 eller 180 dager (purepitch).
Vedlegg
Enig i det.
Man skulle tro at produsenten holdt seg til den lavere enden av halveringstiden, for å sikre seg mot sure kunder og (like viktig) for å selge flere pakker/rør.
Enkelt å overstyre kalkulatorene da, bare å justere datoen til du får sannsynlig viabilitet
