Rehydration of 2 yeast packs

[sictransit701]

Rehydrated two packs of s04 yeast last night. The og was 1.076, so I thought an extra pack couldn’t hurt. I followed my normal procedure not thinking of the yeast to water ratio and rehydrated 2 packs in only 4 oz water. The yeast slurry was thick. How bad off am I? Did I kill yeast?There was bubbling this morning in the airlock.

 

[kh54s10]

The yeast are coated with sterols and nutrients and should be hydrated for only 30 minutes. Both the sterols and nutrients have been used up. The sterols are doing the work of oxygenation, so you should aerated the wort very well. If you have nutrients add them when you pitch the yeast.

Oh, on re-reading your post, I guess that you pitched last night. If not the above applies. I don't think you did any harm to the yeast. Bubbling - I assume in the airlock - shows that fermentation is occurring.

 

[Jag75]

I've never rehydrated yeast . Isnt that just another thing that was done in the past but now shown that theres no reason to . Kind of like secondary vessels?

 

[kh54s10]

I've never rehydrated yeast . Isnt that just another thing that was done in the past but now shown that theres no reason to . Kind of like secondary vessels?

Not for sure. Fermentis has done some studies and has said it is unnecessary. I don't know if they have removed the recommendation from their packages/website. The others may not engineer their yeasts in the same way. Until recently - earlier this year - it was commonly recommended that you always rehydrate for best results. Though it was also common to say that just sprinkling the yeast onto the surface of the wort was acceptable.

 

[BrewnWKopperKat]

I've never rehydrated yeast . Isnt that just another thing that was done in the past but now shown that theres no reason to . Kind of like secondary vessels?

Recent product information sheets for a number of brands of dry yeast:

• https://fermentis.com/en/fermentation-solutions/you-create-beer/
• https://www.lallemandbrewing.com/en/united-states/products/brewing-yeast/
• https://mangrovejacks.com/collections/craft-series-yeasts

Last time I looked (for the strains that I use), my options were to either 1) rehydrate it before adding it to the wort, or 2) sprinkle it on top of the wort.

 

[Jag75]

I've tried sprinkling on top and I've done the mixing . I've had no differences in either way . I've not rehydrated though. I use liquid yeast lost of the time .

 

[HopSing]

My very unscientific opinion based purely on how quickly I see airlock activity, from slowest to fastest:

1) direct sprinkling on wort.
Takes the longest, usually 12-20 hours. Rarely use this method but not closed off to it.

2) Rehydrate for 30 minutes with boiled and cooled water. Slight stirring to break up clumps.
Usually will see activity < 12 hours. This was my go to method, but I always felt breaking up the clumps with a sanitized fork or small whisk could damage cell walls.

3) Rehydrate for 60+ minutes on stirplate with boiled and cooled unhopped wort.
This is the new method I'm trying. Pull off a cup of boiling wort after the initial break has occurred but before first hops addition. Add boiled water until I reach a gravity of 1.025 to 1.030. Cool it to 80F. Pitch dry yeast. Let sit for 10 minutes, then put on stirplate until I'm ready to pitch into cooled wort. I will usually see activity within 10 hours of pitching. This *seems* like the best approach since the yeast can feed and there is no harsh breaking up of clumps.

4) Repitching harvested yeast.
If I use freshly harvested yeast slurry from prior batch, it will usually take off around 6 to 8 hours later. If I use a harvested yeast pulled from the fridge and let warm to pitching temps, then it is about 10 to 12 hours.

Again, this assumes yeast health based on the amount of time I see airlock activity, which could be an absolutely inaccurate way of measuring yeast health and happiness.

The only time I had a batch not attenuate completely is when I pitched rehydrated without breaking up the clumps.

I also offer this:

http://brulosophy.com/2018/11/29/di...tion-with-dry-yeast-the-bru-club-xbmt-series/

~HopSing.

 

[kh54s10]

My experience with lag time is that it makes little difference. I have had activity in as little as a couple of hours. Most of the time I don't know exactly when it starts because I pitch in the late afternoon and it starts sometime during the night. Only twice has there been no activity by morning and that is in over 108 batches.

I don't think stirring the clumps will harm the yeast unless you press the fork against the side of the vessel.

I go by the manufacturers suggestion that you should limit rehydration to about 30 minutes. After that they have consumed the nutrients and the sterols that act as aeration are depleted. Thus they are past the peak of energy.

 

[HopSing]

Poked around and found a recent tips and tricks brochure by Fermentis. Lots of good info if you're interested in the entire dry yeast process:

https://fermentis.com/wp-content/uploads/2019/10/Brochure_Tips_and_Tricks_BAT_BD.pdf

It clearly states my process #3 (using unhopped wort) is not recommended and it should be pitched into hopped wort or sterile water.

I also found the following on https://www.lallemandbrewing.com/en/united-states/products/brewing-yeast/ (click on the rehydration tab)

---
Upon rehydration, dry cell membranes undergo a transition from gel to liquid crystal phase. Rehydration in sterile water is recommended prior to pitching into wort in order to reduce stress on the cell as it transitions from dry
to liquid form. Proper rehydration of dry yeast will produce a highly viable and vital liquid slurry.
The following effects have been observed with nonrehydrated yeast under specific brewing conditions:

• Longer diacetyl stand
• Longer fermentation time
• Longer lag phase
• Stuck fermentation
• Poor utilization of maltotriose
---

Bottom line, do what you're comfortable with and what you believe will make the best final product.

~HopSing.

 

[brewbama]

This how I pitch and pitch rate:

 

[Yesfan]

I always re-hydrate. My method is 4oz of water to a single pack of dry yeast.

1) using a Pyrex measuring cup, I nuke water in the microwave for a couple of minutes.
2) Pour water into a (single wall, no vacuum sealed double wall) stainless steel cup.
3) Set cup in a stainless mixing bowl filled with ice water. I stir the ice water in one direction, while using a stir spoon in the cup stirring in the opposite direction.
4) Cool the water to pitching temps. While I'm "chilling" the water, I have a small pitcher of Starsan nearby that has my yeast pack(s) and scissors in them.
5) Once chilled, I pour the packet into the water and use my (sanitized) stir spoon and I stir in the yeast. I stir until the clumps are gone and it's milky looking. I don't wait for it to settle.
6) Oxygenate the wort with O2.
7) Pitch yeast slurry into fermentor.

I used to do boil the water on the stove, let it cool, let the yeast settle after pitching it in the water, and then slowly stir the clumps away, etc. That just took too long imo. The way I do it now takes no more than 15-20. Before seemed like closer to an hour. I've done this with the last few batches and have not had any issues. Lag times seem to be under 8 hours, but average times have been 4-6. Before with pitching dry, it was more like 12 hours.

To the OP, if you have bubbling in the airlock, you should be good to go. Sorry if I went off topic.