Dry yeast sachets are amazing. They’re easy to use, convenient, and they stay viable for a long time if stored correctly. Sure, there may not be as much selection as liquid yeast, but there’s still plenty of choice and they are of equal quality. Whilst it’s possible to sprinkle the sachet directly into the wort, it can produce a better beer with a couple of extra steps.
When you get your sachet of dried yeast in the post, store it in the fridge asap, this will keep the cell count viable, meaning a healthier fermentation and better beer. Dried yeast can be stored for a long time in the fridge.
When you start to brew, take the yeast out the fridge and let it come up to room temperature over the course of the day.
Oxygenate the wort thoroughly before pitching. This can be done by allowing the wort to fall from a height into the fermentation vessel (FV).
Dried yeast is dormant and the rehydration process gently wakes it up ready to eat the sugars in the wort. Pitching directly into the wort can shock the yeast resulting in a lower cell count. Imagine being woken up and you’re in the middle of a pizza party, it would be pretty shocking.
There’s been some debate online as to whether dried yeast needs to be rehydrated or not. My own experience from making countless batches with dried yeast is rehydrating always makes a better beer. Even when manufacturers’ instructions say to pitch directly, I find I get problems with stalled fermentations, under attenuation, or off flavours from stressed yeast. It’s possible to pitch straight into the fermenter, but for good results pitch two packs.
Rehydration is simple and easy, just make sure to keep everything sanitised as we don’t want to culture up the wrong bug.
- Take a clean container and sanitise it with boiling water.
- Fill the container with 10 times the volume of boiling water to the weight of the yeast. If the yeast is 10 grams, fill with 100ml of boiling water
- Cover the container with sanitised foil (give it a spray with Chemsan) and wait until it’s cooled to 30-40°C.
- Spray the yeast pack and a clean pair of scissors, cut open the yeast and sprinkle it into the warm water.
- Recover with the foil and let sit for 5 minutes.
- Give the yeast a gentle stir until it’s all dissolved and then leave for another 5 minutes
- Give the yeast another stir and it’s ready to be pitched.
I tend to do this half way through my boil. Considering the amount of time I need to finish my boil and cool the wort, it gives plenty of time for me to boil the water, cool it down and carry out the rest of the steps without keeping the yeast hanging around for too long. After a few hours the rehydrated yeast can start to lose viability.