Slow fermentation with harvested Yeast

[DoWBrewer]

I am fermenting a double IPA with a starting gravity 1.078. I am using a second and third generation harvested Cal Ale yeast. I used a two liter starter with oxygen. I also oxygenated the wort.

Typically, I ferment out after 5 days and let it sit for another week. This beer has fermented down to 1.021 after 8 days. I add a pound of sucrose to my DIPA. I boiled that up and added it today. I also added additional yeast nutrient to the boil.

The Gen 2 yeast from was from March and the Gen 3 was from June. The starter fermented for two days before pitching and it was at high kruesen. Any thoughts? Just wait it out?

 

[daksin]

The yeast is kind of old- you may not have had as many cells going into your starter as you thought. Everything else looks fine.

 

[ScrewyBrewer]

I am fermenting a double IPA with a starting gravity 1.078. I am using a second and third generation harvested Cal Ale yeast. I used a two liter starter with oxygen. I also oxygenated the wort.

Typically, I ferment out after 5 days and let it sit for another week. This beer has fermented down to 1.021 after 8 days. I add a pound of sucrose to my DIPA. I boiled that up and added it today. I also added additional yeast nutrient to the boil.

The Gen 2 yeast from was from March and the Gen 3 was from June. The starter fermented for two days before pitching and it was at high kruesen. Any thoughts? Just wait it out?

I use third, fourth and even fifth generation washed yeast too, but gauge the viability of the starters made from them on how fast, or slow, the starter fermentation takes off. As long as the starter, on a stirplate, develops a thick layer of krausen within 8-16 hours I'm confident it will have enough viable cells for fermentation.

I cold crash my starters and then decant them prior to pitching on brewday, so I get to see how thick the layer of yeast cells is at the bottom of the flask before pitching it. A doubling of yeast cells at minimum is what I expect when making a 2 liter starter, from 100b cells to more than 200b cells, although for a higher gravity beer closer to 300b cells may be needed.

 

[DoWBrewer]

I think you are probably correct that I am under pitching. I think I need to invest in a stir plate and prepare my starter sooner. Any other thoughts on how to correct the issue?

 

[DoWBrewer]

I checked the gravity and it has dropped to 1.013 in spite of adding a pound of sugar. I guess it is proceeding nicely after all. I am letting it go for another 10-days for dry hopping. Thanks for the help...