7 year out of date yeast

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j444fog
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7 year out of date yeast

Post by j444fog » Wed Oct 03, 2018 12:32 pm

Found a 40g tub of unopened Nottingham Yeast at the back of the cupboard last weekend. Being short of English Ale type yeasts I decided to see if I could get it to take off in a good quality starter solution. The only problem, best before July 2011.
Dutifully prepared a spray malt starter and pitched the yeast at 28c and placed in fermentation fridge at 28c to see what happened.
24 hours later krausen starts developing and CO2 being liberated.
Time to get a brew on, and post boil added an extra litre of wort to the starter to get it rocking.
By 72 hours it was really going, and smelled good.
I'd already decided that if it took off well I would brew with it, so into the wort it has gone (no other yeast added, so this brew will be all 7yr old Notts yeast).
Temperature in Fermentation fridge set to 19c.
A further 48 hours into fermentation and its bubbling away nicely, smells great, and all appears well.
Has anyone else used massively out of date yeast before? What was the outcome? Any problems encountered along the way? Was the brew as expected at the end?
OG was 1054, MO and Black Malt (0.8%), Amarillo, Cascade and Williamette. One of my Christmas Crackers.

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Blackaddler
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Re: 7 year out of date yeast

Post by Blackaddler » Wed Oct 03, 2018 5:58 pm

As the pack hadn't been opened, the viability was still good, obviously. Storage conditions will affect it to some extent too, but you seem to have done the right thing, and made a starter.

Once opened, viability starts dropping off more rapidly. You can use Mr Malty calculator to see by how much.
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WalesAles
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Re: 7 year out of date yeast

Post by WalesAles » Wed Oct 03, 2018 7:59 pm

Blackaddler wrote:
Wed Oct 03, 2018 5:58 pm
you seem to have done the right thing, and made a starter.
And hopefully made a GOOD BEER! =D>

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Robwalkeragain
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Re: 7 year out of date yeast

Post by Robwalkeragain » Thu Oct 04, 2018 9:36 am

Good luck! Certainly not best practice, haha. I would think viability would be down fairly massively but sounds like you're not having many issues.

j444fog
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Re: 7 year out of date yeast

Post by j444fog » Thu Oct 04, 2018 12:06 pm

So far so good. I'll take a hydrometer reading tonight which should give a good indication on how things are progressing. Everything smells good and the krausen is still there when I took a little peek this morning into the fridge. Looked like the krausen had risen to the top of the FV, which tells me it's quite vigorous.

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Re: 7 year out of date yeast

Post by Rookie » Thu Oct 04, 2018 8:15 pm

Even if it's "out of date" if you account for it in how much you pitch you'll be okay.
I'm just here for the beer.

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Re: 7 year out of date yeast

Post by WalesAles » Thu Oct 04, 2018 8:17 pm

j4,
When you take the Hydro reading, leave the Hydro in the Beer, saves washing and sterilising the Hydro every time. #-o

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Re: 7 year out of date yeast

Post by Top Cat » Thu Oct 04, 2018 9:22 pm

Six months ago I pitched some Nottingham yeast that had past it’s use by date by about a month. After 24hrs from pitching I could see no evidence from the air lock that fermentation had got underway, normally after about 8 hrs it’s on the go. As a precaution I rushed out to purchase another packet, rehydrated and chucked it in. To be fair when I took the top off the bin there was a little evidence that things had slowly started. Fermentation was as normal after that.
I’m not sure whether storage from the supplier could make a difference as on the packet it’s recommended to store below 10c, that ain’t done by the few suppliers I use!

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Kev888
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Re: 7 year out of date yeast

Post by Kev888 » Thu Oct 04, 2018 10:18 pm

There are some impressive results reported from people using quite old dried yeast. It doesn't always come off so is not really to be recommended, but certainly I no longer worry much about a few or several months beyond the date (if storage conditions were good).

Given how old this was though, the starter was a good idea. Its worth noting that after a starter, the yeast need the main batch to be better aerated/oxygenated than the original dried (or rehydrated) yeast would have. But thats not usually hard to do adequately, and IMO well worth the peace of mind of having a successful starter.

That said, it isn't impossible that the reduction in viability favoured certain characteristics over others. I don't recall Nottingham being a dual/mixed strain (though I may be mis-remembering) so hopefully nothing too major. But it will still be interesting to hear if there is anything obviously unusual about the performance - attenuation, flocculation, flavour etc.
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Re: 7 year out of date yeast

Post by j444fog » Mon Oct 22, 2018 12:32 pm

Unfortunately this experiment turned out bad :(
There was a very distinctive off taste of antiseptic / cleaning product. My general theory is that I had cleaned the HLT on the cold side with washing up liquid and not fully rinsed, there did appear to be some very slight foaming action when heating pre Mash, and I thought it was so negligible that it wouldn't affect the taste.
It's either this or at some other point when sterilising and sanitising hot side equipment I hadn't rinsed adequately enough.
The other theory is that the yeast was bad and created the off taste, which is unlikely, as all my research on off tastes indicates cleaning product contamination and I can't find any yeast off flavour advice on the soapy, antiseptic taste, but it could be a possibility.
So down the drain it has gone. As an extra precaution I have cleaned, sterilised and sanitised every piece of equipment I have, and ensured a full rinse.
I brewed this weekend just gone, and taste tested at all stages looking for the previous off taste, and thankfully, it's not present.
I've gone for a brand new sachet of US05 this time for an APA, and it has taken off lovely, and smells sweet as a nut.
So here's to the experiment, not sure what it would have turned out like without the antiseptic off taste, too many variables in the experiment to isolate whether it was the yeast or the cleaning regime.
With the out of date yeast, flocculation was quite low, compared to what I'm used to, and was liquid rather than solid and lumpy. Attenuation seemed OK, FG settled at 1012 (I think OG was mid 50's).

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Kev888
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Re: 7 year out of date yeast

Post by Kev888 » Mon Oct 22, 2018 4:20 pm

Thats unfortunate, it sounds like the yeast kind of worked, but perhaps not so well if they behaved differently wrt flocculation.

Antiseptic is often due to chlorine (from the water or cleaning products) having reacted with the mash, so may be unrelated. But it can also be due to infection which is somewhat more likely if the yeast were slow to beat it.
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Re: 7 year out of date yeast

Post by IPA » Tue Oct 23, 2018 8:06 am

Out of date or in date I always taste the starter before pitching. That way I know if a problem arises it is not due to the yeast.
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Re: 7 year out of date yeast

Post by j444fog » Tue Oct 23, 2018 12:51 pm

I'll be tasting at all stages going forward. If I'd picked up the taste in the HLT water before mashing, I would have started again, but saying that, the contamination could have been cleaning product not rinsed properly from the FV, which I wouldn't have picked up until mid fermentation taste test, (this is normally my first taste test).
Kev, I haven't ruled out an infection either. Although, I don't think I'll be rushing to use out of date yeast again!

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Re: 7 year out of date yeast

Post by Northern Brewer » Tue Nov 20, 2018 7:09 pm

Dry yeast can last a long time in the fridge, they only lose 2%/year or so - but those losses will increase at higher temperatures.

Although Fermentis hotly deny it, Nottingham does seem to be a blend according to those who have played with it in the lab, so a starter will skew the blend, and the stress of long storage may increase the number of mutants you see.

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