1 Posted: Tuesday, May 10, 2016 12:11 PM

All my googling on the topic has just led to a whole lot of conflicting information. There are some that say it's a perfectly good yeast, some even refer to it as a favourite, that even though it's only 7g -when rehydrated and pitched will result in a perfectly good ferment and very drinkable beer at the end. Other's say throw it away and use something like US-05 instead.

I'm far too much of a novice to really know or appreciate the difference and certainly brews I have made so far with either Coopers or US-05 have all been fine. I wondered if anyone has done any kind of A/B testing - identical brews but using different yeasts? I really do wonder if I'd be able to pick the difference, and if I could, would it actually matter?

What I'm thinking, motivated by my desire to minimise costs is that if there's not a whole lot to be gained by using US-05 etc i.e. the apparent benefits are subtle annd on the threshold of taste perception then I might as well save myself the $5.50

2 Posted: Tuesday, May 10, 2016 12:19 PM

I honestly don't know why people go on about throwing the Coopers kit yeasts away in favour of something else. Back when I was using the kits, I pretty much always used the kit yeast, and the beers turned out perfectly fine. It's a pretty good all round yeast I reckon. Unless you're going for a specific yeast driven flavour that only a specific yeast will provide then I don't really see the point in buying more yeast. You probably wouldn't notice a great deal of difference between US-05 and Coopers kit ale yeast fermented at 18C, IMO.

That said, I don't believe 7g of dry yeast is really enough, so perhaps these guys are buying the other packets because they contain more yeast. The Coopers yeast still seems to work fine though, even though technically it's probably an underpitch.

I only really started moving away from the kit yeast when I moved away from kits, because obviously tins or boxes of unhopped malt extract don't come with yeast packets. In this case, you choose your own yeast based on the style of beer you're making.

Now I'm brewing AG, and I have 3 yeast strains that I store in the fridge. US-05, whatever English ale yeast I'm experimenting with, and the Urquell lager yeast. I actually harvest and re-use them multiple times to reduce costs and get my money's worth (the liquid ones are $13.50 a pouch).

3 Posted: Tuesday, May 10, 2016 12:47 PM

Otto Von Blotto:

That said, I don't believe 7g of dry yeast is really enough, so perhaps these guys are buying the other packets because they contain more yeast. The Coopers yeast still seems to work fine though, even though technically it's probably an underpitch.


Yes, I've read that 7g is a bit light and generally considered under-pitching, and there seems to be all manner of debate regarding the implications of underpitching. A lot of the discussion seems theoretical, but again I'm left wondering if anyone could taste the difference in an A/B scenario between a brew pitched with 7g vs 11.5g?

Also, I was thinking that if you rehydrate your dry yeast and let it stand for a while doesn't that immediately increase the yeast cell population?

4 Posted: Tuesday, May 10, 2016 12:59 PM

BlackSands:

Yes, I've read that 7g is a bit light and generally considered under-pitching, and there seems to be all manner of debate regarding the implications of underpitching. A lot of the discussion seems theoretical, but again I'm left wondering if anyone could taste the difference in an A/B scenario between a brew pitched with 7g vs 11.5g?

Also, I was thinking that if you rehydrate your dry yeast and let it stand for a while doesn't that immediately increase the yeast cell population?


Perhaps wouldn't be able to taste a difference in that scenario, depends on how educated their palate is i guess. However, I remember brewing a lager a couple of years ago with some older lager yeast, and although I put it into a starter, I reckon it was still underpitched by a fair margin because the resultant beer was crap compared to the previous year's batches of the same recipe with the same yeast. Definitely off flavours in there which I put down to yeast stress.

Re-hydrating doesn't increase the cell count, what it does is prevents the wort from bursting the yeast cell walls upon pitching it. Dry pitching allegedly kills about half the cells immediately, re-hydrating prevents this (although some may still die, it wouldn't be anything like that amount).

5 Posted: Tuesday, May 10, 2016 1:09 PM

I'm with Kelsey. For an Ale fermented with same yeast 18c and higher I doubt much difference at all whether 7g or 11.5. For a lager big difference. Have done a lager same recipe same ferment temp same everything bar just pitching a packet of W34/70 and while OK it wasn't fantastic. Did one with a 2L starter off the trub of the W34/70 and not only did it finish 3 or 4 days quicker but it a lot different. Better of course.

As far as kit yeast to US-05. Personally I think no comparison. US05 very neutral and allows the malt and hops flavour to shine. The kit yeast nowhere near as clean. My opinion only.

6 Posted: Tuesday, May 10, 2016 1:26 PM

The Coopers kit yeasts are pretty good. My only issue with them is how they were stored prior to purchasing. When you are only using 7g, you want to make sure you have a lot of viable yeast.

No science to back this up other than personal experience, but I think sites like Mr Malty are very conservative with their minimum pitching requirements. Hence why you can ferment a beer with 7g of yeast when Mr Malty states that you need 10-11g.

And whilst we are talking about statements with no scientific support, I will also throw in some hearsay. I know someone that was told by a representative of Fermentis that for a standard gravity beer (I guess up to 1050-1055 mark), there is no need to rehydrate. Even though some yeast may not survive, there will still be plenty of yeast to do the job.

It has been a while since I have rehydrated yeast and have had no problems with fermentation; no problems finishing and no off-flavours. Although for big beers I tend to use 2 packets of yeast.

7 Posted: Tuesday, May 10, 2016 1:36 PM

Otto Von Blotto:

Dry pitching allegedly kills about half the cells immediately, re-hydrating prevents this (although some may still die, it wouldn't be anything like that amount).


Sounds like if the dry-pitch cell death-rate is that high then dry-pitching 7g is effectively pitching with 3.5g ! And yet that's the recommended method I think in Cooper's own instructions? And certainly dry-pitching is something I've often seen in HB videos.


Greeny:

As far as kit yeast to US-05. Personally I think no comparison. US05 very neutral and allows the malt and hops flavour to shine. The kit yeast nowhere near as clean. My opinion only.

I've seen similar comments a lot, and that's what actually got me trying it out for myself. But because I'm not so sure and often confused by conflicting info I tried looking for more ‘sciencey’ assessments - like double-blind A/B testing etc. I did actually stumble across one website where the guy actually does do such comparisons, identical brews with one variable changed, and then the two beers are submitted to an experienced tasting panel for blind tasting and evaluation. Some of the results, of the few I read, were quite surprising and contrary to popular opinions and beliefs. I think he even did a blind A/B yeast comparison but it didn't include Coopers.

8 Posted: Tuesday, May 10, 2016 1:40 PM

Hairy:

It has been a while since I have rehydrated yeast and have had no problems with fermentation; no problems finishing and no off-flavours. Although for big beers I tend to use 2 packets of yeast.


I've only been rehydrating because it seems to kick things off a lot quicker. My first brews I dry-pitched… and they fermented out ok, but they took an extra day to get going.

9 Posted: Tuesday, May 10, 2016 1:44 PM

I think temperature will have a lot to do with it as well. Not that I have done it but if you fermented US-05 and Coopers side by side @ 25c you would get a much different result than if you did a side by side at 18c. Looking at my spreadsheet I have done US05 @ 18c many times and a coopers @ 18c on a similar ingredient brew and the US05 is very clean whereas from my notes the coopers not so. Not that it was that bad or anything.

10 Posted: Tuesday, May 10, 2016 3:12 PM

Greeny:

I think temperature will have a lot to do with it as well. Not that I have done it but if you fermented US-05 and Coopers side by side @ 25c you would get a much different result than if you did a side by side at 18c. Looking at my spreadsheet I have done US05 @ 18c many times and a coopers @ 18c on a similar ingredient brew and the US05 is very clean whereas from my notes the coopers not so. Not that it was that bad or anything.


Another thing I wondered about with regard to temperature was that the Coopers yeast temperature range extends quite high… 28ºC I think? Perhaps it was specifically cultured for Australian conditions!

When I started brewing it was Summer and daytime temperatures were usually in the upper 20's and overnight in the low 20's. I thought at the time Coopers might be the better option because as I had very limited and very crude means of temperature control I thought with it's greater tolerance for higher temperatures it might actually be the better choice under those circumstances. I suspect some of my Summer-time ferments where right on the yeast's upper limit!

11 Posted: Tuesday, May 10, 2016 3:58 PM

You'll find most ale yeasts will happily ferment up that high, and even higher into the 30s. The trouble is though that you end up with a heap of fusel alcohols, and other shit flavours that aren't desirable.

It is a high death rate. I'm not sure if it has been empirically proven yet or not, though. Either way, for the minimal effort required to re-hydrate dry yeast, it's pretty easy to negate the potential risk. The fact they take off quicker when re-hydrated suggests to me that there is some cell death occurring when dry pitching. Less viable cells at pitching means they have to multiply more times before the fermentation begins.

As I understand it, re-hydrating in water allows the cells to regulate much better what passes through their walls. This is key to survival. The osmotic pressure is higher in wort than in water. It is also recommended not to use distilled or RO water for re-hydration, as the lack of minerals in it leads to higher osmotic pressure as well. This pressure ruptures the cell walls, but if they are re-hydrated in a more hospitable environment first, the risk is lessened and more of them survive. Why this pressure doesn't kill 100% of the cells is a bit of a mystery to me though.

12 Posted: Tuesday, May 10, 2016 4:09 PM

Ive made awesome stouts and dark ales using the kit yeasts!

I highly recommend there use…

Ide rather use kit yeast than windser yeast!

13 Posted: Tuesday, May 10, 2016 4:09 PM

Otto Von Blotto:

The trouble is though that you end up with a heap of fusel alcohols, and other shit flavours that aren't desirable.

Yes, had my first experience of that with one of my first Summer-time fermented brews. I didn't monitor the temperature at all and was generally unaware of the need to control the fermentation temp at that time. Daytime temps were around 27ºC, so I'm thinking fermentation temp was actually getting close to 30ºC ! It tasted horrible, very solventy and gave me headaches. It did settle down quite a bit after a few more weeks in the bottle and ended up drinkable, but it was never going to be a good beer! Lesson learnt!

14 Posted: Tuesday, May 10, 2016 4:15 PM

How low temp will the ale kit yeast go before stalling?
Due to poor temp control my current brew is now down to 16 degrees.
Seems to have fermented out ok though.

With the onset of winter imminent I will be implementing better temperature control for future brews.

15 Posted: Tuesday, May 10, 2016 4:17 PM

Ive had the ale yeast double pitch and start fermentation below 16 but I wouldnd risk it for the sake of the brew…

16 Posted: Tuesday, May 10, 2016 4:23 PM

I'd say 16 would be about the lowest you'd want to go with most ale yeasts. Nottingham is an exception, which can ferment down to about 12 or 13 I believe. I usually ferment ales at 18, unless I'm using English ale yeasts in which case I ferment about 20-21.

My first batch was also fermented at ambient in the middle of December Blacksands It was just a Tooheys lager kit with 1kg brewing sugar. I thought it was ok at the time but looking back it was pretty terrible. I quickly moved onto using malt extract and trying to keep the temps down thanks to the advice of this forum. Noticeable improvement. Then I started using the fridge to ferment in and that saw another improvement being able to have the temp constant and where I wanted it.

17 Posted: Tuesday, May 10, 2016 4:23 PM

Waylon:

Ive had the ale yeast double pitch and start fermentation below 16 but I wouldnd risk it for the sake of the brew…


Cool. Pitch temp would have been well above current temp.
Managed to borrow a proper laser temp thermometer which told me real temp 16.2
Stupid cheap stick on thermometer reckons about 20.

Serious temp control and measuring equipment will be acquired before next brew.

18 Posted: Tuesday, May 10, 2016 4:27 PM

Gag Halfrunt:

How low temp will the ale kit yeast go before stalling?
Due to poor temp control my current brew is now down to 16 degrees.
Seems to have fermented out ok though.

With the onset of winter imminent I will be implementing better temperature control for future brews.


I may be facing the same situation soon. Daytime high is around 19ºC but my current brew is still fermenting at around 20 - 21ºC. Another couple of months and I may be buying myself a heat pad…. alternatively it might be time to try brewing some lagers! Only trouble with that is I don't really care for lagers all that much

19 Posted: Tuesday, May 10, 2016 4:32 PM

Yes Kelsey,
Nottingham is unreal yeast how it can handle the lower temps!
I had Nottingham working at low temps as low as 13-14 last winter here, but Ide be using it @16 and raising to 18degrees day four

And if using the Ale kit yeast for a brew ide go 18 degrees and raising to 20 on day 4 to ferment out…

So brewing ales in winter its a must to have some heat control like a heat belt!

No point having aged bottled beer over carbed because it didn't finish off…work the yeast so it finishes to its best ability…

20 Posted: Tuesday, May 10, 2016 4:42 PM

That depends on where you are.. I've never needed heating for ale fermentations in winter, but then again I do brew in a fridge as well so the insulation of that helps maintain the temp, with the heat created by the fermentation itself providing that side of things.

Of course once it dies down it doesn't produce as much heat, so at that point I usually just turn the STC off and open the fridge door during the warmest part of the day, then close it overnight. Works well.