New biabasket set-up/fermentation stuck

[dayfox]

Hello everyone,

After my switch from mashing with motorized stirrer (27L/7gal) to brew in a basket and larger kettle (50L/13gal) I noticed that the fermentation of the same recipe (2x) has stopped.
So now I brew in a kettle with basket, continuous recirculating with hose on top, lying on mash with lid. I occasionally stir things with a large whisk.
The temperature sensor is located in the ball valve at the bottom.
Also grinding malt myself, a bit finer than before without a basket.
Have now brewed this recipe 4x, last 2x stuck:

82% lager malt
10% wheat malt
8% oat flakes

Mash at 65°C/149F, 60 min.
Mash out 78°c/172.4F
Let it splatter in the vessel after boiling.
Yeast lallemand voss kveik:
Start 33°c/91,4F increase to 38°c/ 100.4F every day after 3 days.
Start sg, 1058 (after docking)
Stops at 1030 both times
The only thing that is different now is that I am still messing around with the amount of water.
After the mash and drain basket I am about 5L short. I am still responding to this by heating 5L of distilled water and secretly rinsing the basket.
After the cooling process in the kettle, I came up short the last x 2.1L according to brewfather to get the right starting SG. So I do this by combining it with cool distilled water.
The last x it went like crazy after a few hours! I thought this is going to be all right but still...
Whatever strikes me, after accepting less alcohol-containing (3.2%) I thought, well coldcrash and keg it, it's about the taste.
But after a week no difference! Still cloudy, so finally opted for dumping.

operation:
Taken over on the advice of someone from unibrew (dutch brew shop) I bought safale f2 and according to instructions, 0.07gr / L max, added with yeast nutrient, 5 days ago. Almost no reaction, from 1030 to 1028, MEASURED WITH FLOAT.

Would the temp at the top of the mash be too cold? But isn't it the best way, recirculating?
Or too high, so I don't have enough sugars for my yeast to consume..

I'd like to hear your opinion on experience

 

[Bobby_M]

Lack of complete fermentation is usually either yeast health or the fermentability of the sugar profile created in the mash (or both) but given the use of dry yeast and a low mash temperature would negate both.

The only thing I can come up with is a temperature probe that is out of calibration (low). So you think you're mashing at 149F but really at 159F. In other words, if you found that you were really mashing quite a bit hotter, your high FG measurements would be expected.

The only other thing I figured I'd mention is that this would happen if you were using a refractometer but you already said you've measured with a "float" which I take to mean hydrometer. I only mention it just in case you were using the word float to mean refractometer.

 

[hotbeer]

Or possibly you are only measuring the mash temperature in a area that happens to be a cool part while the rest of the grist is overheated at a higher temp.

I don't recirculate my wort, so I don't know how well that evens out temps throughout or doesn't.

You might check your wort temps and grist temps in multiple places. If you aren't already.

 

[Mac MacFarlane]

Are you measuring the temp of the wort or the room that it’s fermenting in? Possible wort is getting too hot and stressing the yeast?

 

[dayfox]

I did a temp check at the ball valve where the probe is located vs inside the kettle.
Ball valve 63c/145F
Inside kettle70c/158F
Explains a lot!
Also tried something out, a tip from a fellow brewer.
Added a diastaticus yeast to the wort and activity has started again!
Curious what the final gravity will be and also taste!