Open Fermentation and/or Different Fermenter Geometry.

[Twostage]

That'll be interesting. I watch this the other day, that points to fermenter geometry making a difference even with quite similar vessels, without throwing 'open' into the mix.

It was interesting. As you say 'open' wasn't in the mix but the corny v. carboy pointed to short and fat being better than tall and thin.

 

[Sadfield]

What is interesting is, it's brulosophy returning the conclusions that such a small change makes a difference, both perceptably and statistically. Usually, their xbeeriments and 'short and shoddy' articles don't, despite some seamingly dramatic changes to process.

 

[MashBag]

short and fat being better than tall and thin.

It is also the favourite of winemakers, so perhaps it follows?

 

[Twostage]

It is also the favourite of winemakers, so perhaps it follows?

Maybe indeed. I'm looking forward to my open v. closed fermentation test. I just need to finish the Staropramen clone (which I've just started the diacetyl rest) so I can use the brew fridge or a run of cold weather so I can use the heat only brew chest freezer. OR I could do a kviek.

 

[MashBag]

How open? No airlock or nothing?

 

[Twostage]

How open? No airlock or nothing?

This open...

 

[Sadfield]

Thread 'Spingo Blue Anchor' https://www.thehomebrewforum.co.uk/threads/spingo-blue-anchor.35148/

 

[Twostage]

This open...

View attachment 103281

My brewfridge will be free later today/tomorrow so I thought I'd better check the gastronome fits. It fits perfectly on the shelf supports things as if it was a shelf itself. Marvelous.

Going to do a user-upper brew with a fairly 'plain' hop recipe.

 

[matt76]

Altbier Open Fermentation Update:
View attachment 102852
Well for better or worse, it's been 5 days since pitching so I've kegged it. I pre-pressurised it to 5psi just to make sure the lid is seated and fitted a new "Spundy" spunding valve with a pre-set 15psi PRV.

The krausen never fell and I was surprised to find the SG has only gone from 1.044 to 1.019...

Reading around the web it seems like K-97 tends to have, or can have, both these characteristics. I haven't used it much before - first time in a very similar beer it went 1.044 -> 1.015. The next time it went from 1.042 to 1.009 but in that case I re-pitched slurry so maybe it's a pitch rate thing

In any case I think it's a yeast thing and not an open fermentation thing. I'll leave it a few days and see what happens to the pressure gauge and if need be I'll make a small starter of US-05 and throw that in to see if that gets it moving again.

For all that, the hydrometer sample tasted very nice indeed, it didn't taste at all "not done yet" - malty with some berry esters, kind of like a lager meets bitter.

Another Altbier Update:
I had a first taste last night and unfortunately it was rather disappointing The yeast hasn't settled out though I'm not really sure why as gravity had been stable for a while before I dropped the temperature. I've chucked in some gelatin which normally does the trick and I'll try it again in a week.

I'm quite certain it's an issue with K-97 being an awkward strain to work with (my Googling tells me Wyeast 1007 is similar in every sense) so I'm not too worried - I've fixed worse beers than this before!

I suspect it's a pitch rate thing - the one time I had a straightforward fermentation with K-97 I re-pitched some harvested slurry so probably had a bigger pitch rate than half a pack of dried yeast which is usually sufficient for my small batches.

 

[Twostage]

Another Altbier Update:
I had a first taste last night and unfortunately it was rather disappointing The yeast hasn't settled out though I'm not really sure why as gravity had been stable for a while before I dropped the temperature. I've chucked in some gelatin which normally does the trick and I'll try it again in a week.

I'm quite certain it's an issue with K-97 being an awkward strain to work with (my Googling tells me Wyeast 1007 is similar in every sense) so I'm not too worried - I've fixed worse beers than this before!

I suspect it's a pitch rate thing - the one time I had a straightforward fermentation with K-97 I re-pitched some harvested slurry so probably had a bigger pitch rate than half a pack of dried yeast which is usually sufficient for my small batches.

but... what does it taste like ?

 

[matt76]

but... what does it taste like ?

Yeasty!

There's so much yeast still in suspension that it's masking anything else. But I'm confident the gelatin will have done it's job by next weekend and I'll be able to give a more considered verdict

 

[Sadfield]

Fingers crossed.

The forced ferment I'm doing in parallel only got down to 1.015

From 1.044 that's only 65% attenuation which is very low for K-97, it normally goes into the 80's. There could be a yeast viability issue, making the ferment very laggy. What's the gravity?

 

[matt76]

Fingers crossed.


From 1.044 that's only 65% attenuation which is very low for K-97, it normally goes into the 80's. There could be a yeast viability issue, making the ferment very laggy. What's the gravity?

1.014

You could be right, BUT.....

- I would argue (indeed, you and I have argued about this before! ) that 2-4 of those gravity points are not (or at least not very) fermentable as they come from 80L dark crystal and Carafa Special 3.

- Standard practice for me is to make a shaken not stirred starter - based on this and the way the krausen formed I think fermentation certainly started well until it got stuck around 1.020.

-Searching the web (including right here on THBF) it seems like K-97 is prone to stalling around 1.020. Certainly I don't think I've ever had this trouble with any other strain, dry or liquid.

- The sample I took when I transferred to a keg at 1.019 was actually pretty clear and tasted really good. But I also added some US-05 to try to get it to finish off which might have been what has caused my issue!

- Certainly it kept fermenting a bit more because it (a) carbonated the keg and (b) I kept a sample in the hydrometer jar which was visibly fermenting.

 

[RoomWithABrew]

I've not had problems with wyeast 1007, ferments really well and drops with cooling and then some super F.

 

[Twostage]

Made a use them up brew today to do a split batch open/closed fermentation. Gains included - Maris Otter, extra pale organic, Vienna, Munich 1, dextrin and possibly something else. Hops were Herkules, Fuggles and Calypso. Goodness knows what its going to taste like. Anyway, ended up 1.052, pitched Nottingham at around 17c.

I know the closed isn't sealed but I think its closed enough.

This is where the spent grains ended up...

 

[Caramel Ox]

Can’t you take the tube out or seal round it with clingfilm?

 

[Twostage]

Can’t you take the tube out or seal round it with clingfilm?

The tube is a temperature probe and I'd like to keep that in. I could do the cling film thing though.

 

[RoomWithABrew]

Just tape and insulate the probe on the outside of the pot. I use blu tack and then hi density foam held on with a bungee cord.

 

[Twostage]

Just tape and insulate the probe on the outside of the pot. I use blu tack and then hi density foam held on with a bungee cord.

I used to do that but found that even with several layers of insulation it still picked up temperature changes of the chamber.

 

[RoomWithABrew]

I think the big piece of blu tack adds thermal stability. I don't heat the chamber but use a heat belt on the fermenter and then have insulation around the outside 2/3 of the pot.
But not the base or lid so the cooling can act.