How to stop a brew stalling (and then going bad)

[Mattrox]

Shouldn't start yeast off on dex/sugar as I understand they get used to the simple sugars and are lazier/less efficient with the complex sugars from the malt. If anything make a 1.04 wort with LDME. Can rehydrate the yeast in 100ml of water for up to 30 mins, no need to go longer.

Dex I agree with but sugar (sucrose) is no more simple than maltose. Both are disaccharides and need hydrolysis for yeast to utilise.

There might be other benefits malt over sugar given malt will have nutrients and minerals that help yeast stay healthy.

 

[gone brewing]

Maybe you could find an experienced brewer who is willing to help you out with this (and their beer is OK).

You buy 2 sets of ingredients. You make up one set and the other brewer does the other. Prepare the ingredients and ferment them in the same way (temperature and time). Then you compare results. Could be a guide as to what is going on.

 

[Mattrox]

I did a bit of reading about yeast utilizing sugars. There are different pathways that yeasts use to get the sugars inside glucose/fructose, sucrose, maltose, maltriose. There are competing processes and yeast shift the method depending on what is available. They can shift, but I guess what we observe is a lag time if we use a different solution of sugars in the culture than is in the wort. But the yeast can easily change mechanisms of sugar uptake.


Of note, but off topic, was a bit about at the end of fermentation when there are residual sugars. Fructose is detectable at lower concentrations than glucose. When the yeast has given up fermenting, if there is a large amount of sucrose in the wort, the residual fructose from it is detected as a sweetness. If there are glucose molecules at the same concentrations we don't perceive it to be so sweet.

 

[pablo_h]

The process I mentioned before is not my usual, it's what I'm changing to fix a problem.
When I started out, it was just like the old directions. No boiling sugars, no proofing yeast. Just kit, and kilo of sugar, boiled water to mix/dissolve, top up with tap water, sprinkle with kit dried yeast, stir in with sanitized spoon. This method failed for me, never trying it again, don't suggest it.

Then I though it was the sugar, so I switched first to dextrose sugar, then coopers BEs, then buying liquid or dry malts. Didn't fix the problem.
Then I started boiling all the above first, didn't help.
Then I thought it was water, so preboiled water too, didn't help.
Then I thought I was not cleaning properly, so I bought starsan.
Then I thought it may be scratches and whatnot that even starsan couldn't fix, so bought new fermenters.
Then I thought it was the stirring, so went back to just sprinkling the dry yeast on top - not rehydrating/culturing, not stirring or touching the yeast much at all. That didn't help so I thought buy better yeast. I know I tried so4 and so5 during winter months years ago, I think these brews worked out, so this is why I started this thread saying yeast problem maybe. Not sure if they're worth using now in hot weather where the lowest temp I can do is 26C though, so this thread is about working with coopers yeast.
This current method I posted earlier was just a new thing I'm trying, not what I've always done.

Anyway, back to the present.
I'm running all three fermenters I have right now, if running an a/c over the hot days may as well get more value for money...
Ones got coopers ginger beer so forget that for now
The other two have coopers lager.
Both were started 10hrs ago. One with the preboiled wort and precultured yeast, the other just has had boiled water and rehydrated yeast (has seen no dex or sugar prior to pitching).

The preboiled/cultured fermenter has gone bonkers, krausen up to the airlock (that's not really a good thing, messy to clean up afterwards etc I know), but never had a yeast start so strongly so that's a good sign at least (Edit: I hope. I hope it's not just going to burn out early on the dextrose and stall at the malt - anyway, we shall see if a quick start is better than a lslow and steady burn the other fermenter has). Not much foam in the other fermenter, just barely starting to bubble now while the other one started bubbling 6 hours ago.

We'll see if any stall, and what they come out like flavour-wise.

 

[pablo_h]

Update.
I was a bit worried because the airlock stopped bubbling on the above first brew after 2 days
I know I shouldn't have messed with it, but I needed to know.
Took a S.G. sample and it was already at 1010

Just going to leave it now as the cool weather in Perth means I can just sit back and not worry about cooling/temp control (besides shutting the window at night) at least until thurs/fri anyway. So I'll let it finish off, clean up and clear up undisturbed for a while.

Was a bit susprised how bitter/dry it tasted. I know that's because I used some dex, not all malt. But I'm just glad I didn't do a toucan now as I'm not a fan of overly bitter beer as the hops extract in the kit seems pretty strong*
Speaking of which, the brew that I added no sugar to the yeast (in order to get a starter/jump start), is still slowly going. That yeast was rehydrated too though - just slower to start and looks like it's going to be slower to finish - I hope it wasn't underpitched.

Prevously because all of my problems, beers that "semi-worked"came out too sweet as they stalled, so that's why I switched back from all malt to half dex.
Next time I'll go all malt.

*E: anyone found the coopers lager kit is more bitter than coopers ale?
I know the ale that failed never tasted this bitter (from the can as I did sample both for curiosity). Maybe something has been wrong with the kits I have bought in the past if the ale was supposed to be more bitter than this lager kit.

 

[pablo_h]

The winner is:
Not using dex to prime yeast.
Of course not rehydrating dried yeast is the ultimate loser, because that never worked for me, at all, ever.
The primed/stated/cultured kit cooper lager got to 1010 SG in two days, but stuck there. Better than an infected brew stuck at 1020 though.
The rehydrated only kit yeast took way longer (and is still going at ~1008). Going to dry hop it with goldings for ***** and giggles.

Rehydrate your yeast!
E: and maybe in the future get temp control and better yeast (or become an autumn only brewer)

 

[bevan]

I've been doing extract brews for the last two years and thing that improved my beer was controlling the fermentation temp. I have an stc-1000 that I set to 20 deg (I've only brewed ales), controls the fridge and heat pad. Since doing this my beers have been tasting awesome!
I don't use the yeast supplied with the can. I use decent dry yeasts (mostly safale from my local HBS) and just throw them into the wort when it's below 24 deg (usually 22 deg) giving it a good stir. As I normal make up my wort at night I'm not to sure how long it takes to get going but by the morning it's bubbling gently and takes about 10/14 days to fully ferment out (due to working shift work it might then sit there for another 4/6 days before I bottle it).
The first brew I did (long before ferment temp control) I did in my laundry and had on a heat pad (advise from HBS) on. Was mid winter in Melbourne. The ferment temp got up to 28 deg and stalled. I ended up putting in more yeast and got the temp down to get going again, beer was so so in taste. Since then I haven't had any stalling by keeping my temps under 24 deg. Before having the fridge (and being banished from the laundry by the minister for war/finance because of the odd exploding bottle) I'd regulate ferment temp by opening or closing the laundry door, ah the good old days!
I think if you can keep the ferment temp down you should get good beers.
I'm sure there are more experienced people on the forum who can give you great advice but for me temperature control was the big improver!
I also think your being a bit harsh on yourself.
Cheers
Bevan