Very slow ineffective ferment

Get advice on making beer from raw ingredients (malt, hops, water and yeast)
Muscleguy
Tippler
Posts: 24
Joined: Thu Jun 11, 2020 1:47 pm

Very slow ineffective ferment

Post by Muscleguy » Thu Apr 01, 2021 10:05 am

Scottish Heavy, Simpson's golden promise pale malt, 50/50 dark crystal/carared, dark brown sugar. Temperature adjusted post boil OG 1.043. Yeast rescued from a bottle of Shepherd Neame 1698, I have done this before to excellent effect.

Initial ferment was good, good head. I dropped it after 2 days 1.032. No new head formed so tight lid with grommet and airlock. That was 8 days ago. It is now 1.022. Two days ago I dropped it again introducing lots of air and more yeast nutrient. It is very fizzy so it's making lots of CO2 but feck all alcohol.

Heat belt around it 21C nice and toasty, not too high.

Mashed for 2 hrs at 65/66C. Two sparge batches for 77C in the mash, left 15min each. Good slow runoff, no stuck mash. Old style hop levels Fuggles, Goldings, Mandarina Bavaria.

It's sitting there belching big lots of bubbles every couple of minutes but it's 2.75% by the calculators. Not exactly 80/-

My strong, rich, dark winter ale is fantastic. Just finished a barrel of Dunkelweizen, got a gallon bottled to look forward to. No such problems with either of them.

Ideas please.

nickjdavis
Steady Drinker
Posts: 59
Joined: Thu Apr 11, 2019 3:10 pm

Re: Very slow ineffective ferment

Post by nickjdavis » Thu Apr 01, 2021 1:46 pm

deleted
Last edited by nickjdavis on Thu Apr 01, 2021 1:49 pm, edited 1 time in total.

nickjdavis
Steady Drinker
Posts: 59
Joined: Thu Apr 11, 2019 3:10 pm

Re: Very slow ineffective ferment

Post by nickjdavis » Thu Apr 01, 2021 1:48 pm

deleted

Muscleguy
Tippler
Posts: 24
Joined: Thu Jun 11, 2020 1:47 pm

Re: Very slow ineffective ferment

Post by Muscleguy » Thu Apr 01, 2021 1:50 pm

Syphoned from one container to a new one. Likely done by gravity in a brewery hence dropped. Leaves the old dirty head and the trub behind.

Muscleguy
Tippler
Posts: 24
Joined: Thu Jun 11, 2020 1:47 pm

Re: Very slow ineffective ferment

Post by Muscleguy » Thu Apr 01, 2021 1:53 pm

I did it the second time to get it off the accumulating trub. There was a thick layer on the bottom of the bucket.

nickjdavis
Steady Drinker
Posts: 59
Joined: Thu Apr 11, 2019 3:10 pm

Re: Very slow ineffective ferment

Post by nickjdavis » Thu Apr 01, 2021 1:55 pm

Yeah I realised what you meant after re-reading...if youve done it before successfully then shouldnt be a source of your problem. But TBH I'm not sure that its really necessaary. Beer can sit on trub for a reasonable time without real issue.

What is your predicted FG?
Last edited by nickjdavis on Thu Apr 01, 2021 1:57 pm, edited 1 time in total.

Muscleguy
Tippler
Posts: 24
Joined: Thu Jun 11, 2020 1:47 pm

Re: Very slow ineffective ferment

Post by Muscleguy » Thu Apr 01, 2021 1:57 pm

I drop all my beers and this is the first time I have not had a new head form afterwards. Just islands of bubbles hence having to use a tight lid with airlock. It would appear to indicate a lower level of ferment not sufficient to establish that new head.

It was 15litres and included 450g of dark brown sugar so there is no lack of ready fermentables in the wort.

Muscleguy
Tippler
Posts: 24
Joined: Thu Jun 11, 2020 1:47 pm

Re: Very slow ineffective ferment

Post by Muscleguy » Thu Apr 01, 2021 1:59 pm

FG should be around 1.007 predicted start was 1.041 so I slightly overshot that. But at 1.022 now it still has a way to go.

It's the Harviestoun recipe from Wheeler & Protz's book.

User avatar
Eric
Even further under the Table
Posts: 2873
Joined: Fri Mar 13, 2009 1:18 am
Location: Sunderland.

Re: Very slow ineffective ferment

Post by Eric » Thu Apr 01, 2021 2:16 pm

Not used Shepherd Neame yeast, but we'll assume it is a good top fermenting ale yeast and what you describe suggests fermentation is basically completed. Lots of bubbles every few seconds also suggest fermentation is mostly finished, and a good ale yeast will likely be finished in 3 or 4 days.

Yeast cannot ferment sucrose until it is converted to fructose and glucose by invertase, an enzyme that yeast can provide. Weakened yeast might be only able to provide limited quantity of invertase which would slow the fermentation process.

Is your measurement by hydrometer or refractometer? The latter wouldn't give a reliable reading once fermentation began and alcohol was present.

Oxygen is advantageous in the earlier stages of fermentation, but undesirable in later stages, although that cannot now be undone, just to hope the yeast will consume all that remains.
Without patience, life becomes difficult and the sooner it's finished, the better.

Muscleguy
Tippler
Posts: 24
Joined: Thu Jun 11, 2020 1:47 pm

Re: Very slow ineffective ferment

Post by Muscleguy » Thu Apr 01, 2021 4:38 pm

I only introduced more air in the last dropping since it was the only thing I could think of doing to try and get things moving again. The first one where the head did not form again was done to exclude as much air as possible as is good practice.

The sucrose point is a good one which is of course why we use dextrose (inverrt sugar) to prime with. I was jus worried I had done something wrong in the mash.

I remember I almost forgot to add the sugar to the boil, so only the last 25min then the post boil steeping. A longer boil might convert more of it from the acids present to invert sugar. So that may be the reason for the slow ferment.

I'm slowly getting better from viral meningitis, it came back after my Covid vaccine so I shall blame that for my memory lapse wrt the sugar which should have had a good hour on the boil.

Muscleguy
Tippler
Posts: 24
Joined: Thu Jun 11, 2020 1:47 pm

Re: Very slow ineffective ferment

Post by Muscleguy » Thu Apr 01, 2021 4:39 pm

Whoops, last 15min there. It went in with the aroma hops.

User avatar
Eric
Even further under the Table
Posts: 2873
Joined: Fri Mar 13, 2009 1:18 am
Location: Sunderland.

Re: Very slow ineffective ferment

Post by Eric » Thu Apr 01, 2021 7:29 pm

Thanks for your report, it does expand on your objectives, although you didn't confirm your gravity reading was by hydrometer, for had it been derived from an uncorrected refractometer reading, the actual gravity would be significantly less.
Muscleguy wrote:
Thu Apr 01, 2021 4:38 pm
I only introduced more air in the last dropping since it was the only thing I could think of doing to try and get things moving again. The first one where the head did not form again was done to exclude as much air as possible as is good practice.
Oxygen and yeast is complicated. Dried yeast usually comes with sufficient, but pitched live yeast may previously have been working anaerobically, thus needing a plentiful initial supply to get going, while some strains demand more to build an adequate population to finish the job. It was a long time ago, but I did go through a phase of dropping wort to a second FV. Eventually I recognised stopping the crap getting into the FV in the first place, totally removed this step.
Muscleguy wrote:
Thu Apr 01, 2021 4:38 pm
The sucrose point is a good one which is of course why we use dextrose (inverrt sugar) to prime with. I was jus worried I had done something wrong in the mash.
I remember I almost forgot to add the sugar to the boil, so only the last 15min then the post boil steeping. A longer boil might convert more of it from the acids present to invert sugar. So that may be the reason for the slow ferment.


Very little sucrose can be inverted in boiling wort while typically at pH 5. As described here in the second paragraph after the picture, it is inverted commercially between pH 1 and 1.6, although not as hot.
Muscleguy wrote:
Thu Apr 01, 2021 4:38 pm
I'm slowly getting better from viral meningitis, it came back after my Covid vaccine so I shall blame that for my memory lapse wrt the sugar which should have had a good hour on the boil.
Sorry to learn of your problem after vaccination, that's awful. I've had both, with no reaction whatsoever after the second. My wife had a worse reaction after her first as did one of our sons-in-law after his, but nothing compared to yourself. Hope you have a quick and full recovery.
Without patience, life becomes difficult and the sooner it's finished, the better.

Muscleguy
Tippler
Posts: 24
Joined: Thu Jun 11, 2020 1:47 pm

Re: Very slow ineffective ferment

Post by Muscleguy » Thu Apr 01, 2021 7:54 pm

I haven't done a pH of the boiled wort but my mash is usually at pH4, a benefit of soft acid water to start with here in Dundee. Add in hop acids and it may even be lower. No point testing it now with all the dissolved CO2 of course.

As I said I got good head, not very thick but that varies with the recipe. So I think I got enough O2 in there at the start. I always do a starter bottle, essential when rescuing yeast from a bottle of course but generally good practice. My father back in '79/'80 did evening classes in brewing wine and beer. He was experienced with wine (family tradition) but not beer. He swore by a starter bottle afterwards.

Though I don't use DME for it for wine or cider as he did. I have a little notebook he used to record his brews. It was only half used so I have continued to use it in memory of him, noting where I take over for posterity.

Thanks for your good wishes though.

Muscleguy
Tippler
Posts: 24
Joined: Thu Jun 11, 2020 1:47 pm

Re: Very slow ineffective ferment

Post by Muscleguy » Mon Apr 05, 2021 10:22 pm

It all ground to a halt, no OG movement since original post. No more burping.

So I bought a sachet of Beoir a yeast for Scottish and Irish brews, hydrated, it added it and regularly burps again.

It might just be that a yeast from the purists (no slur) at Shepherd Neame might not have been the best choice for a beer with a fair amount of sugar in it.

One to remember and put down to experience.

BTW got the Beoir from the excellent friendly folk at Crossmyloof brewing. Very reasonable if not free shipping too.

User avatar
MashBag
Even further under the Table
Posts: 2137
Joined: Wed Oct 23, 2013 7:13 am

Re: Very slow ineffective ferment

Post by MashBag » Tue Apr 06, 2021 6:56 am

Muscleguy wrote:
Thu Apr 01, 2021 7:54 pm
I haven't done a pH of the boiled wort but my mash is usually at pH4, a benefit of soft acid water to start with here in Dundee. Add in hop acids and it may even be lower. No point testing it now with all the dissolved CO2 of course.
If you think you have done a rousing, try adding 1/2 tsp bicarb.

This could be a water issue.... too acidic for the yeast.

Post Reply