Yeast rehydration - an anomaly

[Danzar]

I've started rehydrating my yeast. The little blighters go in 100ml of warm water (probably just over 30c) for 30 minutes.

Now, I thought this was meant to get your yeast chowing through your malt quicker.

My brews are actually starting fermentation later as a result of rehydration - up to 24 hours after putting a batch down.

Would there be any other reasons for this? Perhaps the water is too hot?

[Aussie Claret]

Danzar,
The rehydration temperature is right on the money, if you are experiencing long lag times I'd be looking to other reasons, perhaps the wort hasn't been aerated sufficiently.

Just one question with your rehydration before you pitch, has the yeast started foaming up? it should have a foamy head after 30mins.
Cheers
AC

[Chris]

Yeah, as AC said wait for head. Try proofing your yeast too, just to make sure you have a high enough number of viable cells.

You could also try stepping up your starter, or even adding a nutrient if you are worried about lag time.

[rwh]

Try proofing your yeast too...

What's proofing?

[Chris]

Adding a bit of malt (or wort) to the yeast once rehyrated, to check for yeast activity.

[Aussie Claret]

The foaming up is already proof that the yeast is working. With dry yeasts you shouldn't be making a starter or stepping up, the manufacturers actually say that this can be detrimental as it can deplete the initial energe reserves that the dry yeasts have.
Also most dry yeasts have sufficient cell count to ferment correctly, I say most because if you are making a higher gravity beer then you may need a higher cell count and also some lager dry yeast (saflager DCL) yeasts come in 11.5g packs depending upon the pitching temperature (if cool) you may require two packs.

AC

[Danzar]

Wort was aerated. First batch - no head. Took two days for fermentation to start.

Second batch - head.

Took about a 24 hours, give or take. It's possible that fermentation started earlier but if it did, it was extremely mild. Used a K97.

Must say that now, this second batch is fermenting furiously.

I may just drop the temp next time just to be safe. The 30c was an estimate and it may have been a bit too warm, particularly with the first batch.

[chris.]

One thing also worth watching is the temperature difference between the rehydrated yeast slurry & the wort. I rehydrate, leave for 10mins, add 100mls of wort & leave for another 5-10min, then add another 200-300ml of wort, leave for 5mins then pitch.

[Ed]

One thing also worth watching is the temperature difference between the rehydrated yeast slurry & the wort. I rehydrate, leave for 10mins, add 100mls of wort & leave for another 5-10min, then add another 200-300ml of wort, leave for 5mins then pitch.

What a clever way to help reduce shock. I'll adopt that

Cheers, Ed

[Danzar]

One thing also worth watching is the temperature difference between the rehydrated yeast slurry & the wort. I rehydrate, leave for 10mins, add 100mls of wort & leave for another 5-10min, then add another 200-300ml of wort, leave for 5mins then pitch.

What a clever way to help reduce shock. I'll adopt that

Cheers, Ed

Definitely clever. It will also give me something to do while waiting.

[mark68]

My yeasts always start within 5 to 6 hours after rehydrating,so i can only guess that you're temperature must be wrong to have to wait 24 hours to start a yeast.I also use use a yeast nutrient,around 5 grams for 22 litres.I don,t know what difference this stuff makes,but i use it anyway.

[dags64]

I put down a brew recently and the yeast was working about 4-5 hours after pitching
I used SAF US-56 yeast rehydrated in 300 mls of 37 degree water with half a teaspoon of sugar for 15 mins then pitched into the brew which was at 23 degrees

[morgs]

just sprinkle on top it wil soon rehydrate

[pacman]

I'm with you morgs.

Have tried rehydrating, but haven't noticed any benefit. Now I sprinkle the dry yeast on top of wort immediately after a good stirring.

Honestly, can't notice any difference, except not having to gin around getting water & yeast at right temps, and then waiting mandatory 10 minutes or so before pitching.

I'm trying to keep it as simple as possible without detracting from the quality of the final product. If I have problems, I will look at revisiting rehydrating, but at present this appears unlikely.

[Pale_Ale]

With dry yeast, I've had the best results from just sprinkling on top while the wort is still swirling.

Sorry to digress a little, but on a related issue, who steps up their yeast cultures prior to pitching and is it necessary or beneficial?

[Aussie Claret]

Sorry to digress a little, but on a related issue, who steps up their yeast cultures prior to pitching and is it necessary or beneficial?

Depends on whether you are using dry or liquid yeast. With dry yeasts you shouldn't be making a start or stepping up, if you require more yeast then pitch more than one packet. For liquid yeasts it is generally recommended to step up the yeast to ensure you have sufficient cell counts.

Cheers
AC

[BeerisGoode]

G'day,

Don't know if this is really relevent but I've been using a shower extension hose to top up the fermenter. (connect it to the tap and other end like a shower head). Its a bit of a pain to clean but MAN does it aerate the wort. Just using dry yeast I've had activity within 3 hours at 24c.

Is it possible to OVER aerate?????

cheers,

BeerisGoode

[Aussie Claret]

no

[rwh]

Haha well somewhere on here someone posted about their first brew where they left the airstone on for like the first 3 days! Yeast don't ferment in the presence of oxygen, they just make CO2 and water!

So I guess the answer is yes...

Might be a good way to make light beer?

[gregb]

Turn off the aeration when yeast is pitched, and you will struggle to over do it.

I recall hearing, I think it was the BN, that you can over oxygenate if your are piping straight O2 into your wort, but when pumping air you could not over aerate.

Cheers,
Greg