Curiosity: OG goes *UP* afterstart of brew!?

[Victor Churchill]

Hello, thi seems a bit odd.
I started off a Bulldog Evil Cat a week ago. iSpindel said it started at 1065 and then after a few hours went UP to 1071, stayed there for a few hours then camee down quite rapidly over the course of a couple of hours to the level you'd expect if it was behaving 'normally'.
Snapshot of the BrewSpy graph:

BrewSpy has given me a share link but it's only valid for six hours from now so will expire just before 1 a.m. on 7 Dec :
Bulldog Bad Cat Imperial Red #1 - 6.68% - 72%

Since the rest of the graph looks 'normal' I am wondering if this is just an anomaly of some sort? I thought it could be the brew not being evenly stirred and the iSpindel finding a denser patch but that feels very improbable.

 

[Clint]

My suspicion is that the brew wasn't properly mixed up at the start. A very common occurrence.

 

[jayk34]

Could be the CO2 from the fermentation forcing the ispindle up.

 

[Victor Churchill]

My suspicion is that the brew wasn't properly mixed up at the start. A very common occurrence.

That was my first thought too, reassuring to know it's not uncommon...

Could be the CO2 from the fermentation forcing the ispindle up.

... but that's a very interesting idea. bit of CO2 adhering to the iSpindel would have that effect on the readings, while it's hard to imagine denser brew rising to the top to make the device think the SG has risen.

 

[RoomWithABrew]

How's this for a theory?

For the " gravity " reading to go up the ispindel would need to become more towards the horizontal. Looking at my ispindel calibration notes for three ispindels that would be in the region of about 2 degrees. Seems unlikely that a ferment would get going so violently in 6 hours to sustain this angle change for about another 6 hours. The temperature change is not likely to have affected the gravity that much either although you do see a corresponding rise in temperature that mirrors the gravity rise.
It's more likely that as the wort was warming it allowed some less well mixed higher gravity wort to rise and that changed the density for a while until mixing occurred by the convection currents and fermentation starting / progressing.
I don't think this would be a krausen factor on the lid either as it's very early and would shift the ispindel angle from the point onwards, your angles don't do this.

Getting a good mix with kits using extract is tricky, often appears that it's mixed but really just whirlpooled towards the middle, lots of direction change and side to side use of the spoon helps with the mix and a lot of patience. Leave it for a while have a beer then come back and remix.
It's good to get a lot of air ( oxygen) into the wort with the new yeast in there.

It should be fine.I'm surprised how slow that yeast is though I tend to see better performance from yeast than that. Update us on the taste in a few weeks.

 

[RoomWithABrew]

@Victor Churchill

In brewspy try settings then select smooth graph.

Should get a much nicer looking graph.

It's got a few gravity points to go yet as the profile not flattened out yet.

 

[Eskimo John]

I had this issues with a very active fermentation with my ispindel. At the end of the brew I found the ispindle had a lot of debris on the cap of the device which I assume had had an impact on the way it floated and therefore the readings it gave.

 

[Victor Churchill]

Good points @RWaB. I do try to give the wort a bit of welly as I am mixing it, not just round and round but edge to centre like mixing a pudding, but that's more during the initial mix when there's more room to shake it about. (I also like seeing how high I can hold the pan as I pour in saucepans-full of water to top the wort up). I like the idea of pausing for a beer then coming back to remix )

Bulldog do say on their instructions that it's a quite slow yeast and to allow 8 to 15 days, and I always allow at least a couple of weeks.

Re. graph smoothing, I'm not sure I trust the smoothing algorithm and think I'd rather see the actual data, lumps and bumps and all!

@EJ, I'll check the iSpindel for cleanness when it comes out. It did tot give the impression of being a very vigorous fermentation.

 

[RoomWithABrew]

Accept the fact that there will be some yeast on the ispindel whatever you ferment, it will not be as clean as when you drop it in at the start. The ispindel is sensitive enough to be affected by atmospheric pressure changes. Definitely affected if pressure fermenting.
Graph smoothing doesn't really throw away the data it just averages out the dots. The trend is the same but easier to read.
If you select smoothing and have a look at the graph and it's not good enough for you turning the option off reverts back to the original.

 

[jayk34]

I really like the ispindle. It's not always totally accurate due to the reasons outlined above but gives you a very good indication of when fermentation is coming to an end as the graph will level out and the temperature drops due to the reduced exothermic activity.

 

[DixeySJ]

I noticed this once I started live monitoring with a Tilt. My theory was that the increase in gravity was due to the proliferation of yeast cells before they started producing alcohol enough to reduce the SG again. Sometimes it happens, sometimes not. I don't find that the Tilt readings are always objectively accurate, but I am mainly interested in relative change over time. I always check my OG and FG with a hydrometer.

 

[RoomWithABrew]

I agree with @DixeySJ great for a trend but do use hydrometer temp corrected for OG and FG.
The setting the original gravity feature ( as measured on hydrometer ) is very useful in brewspy. You then get two graphs, having done this for a while basically the offset seems to stay consistent, so if measured was 1056 and ispindel says 1053, when final gravity end of ferment is reached the reading will be 3 points lower on ispindel than actual. But it doesn't account for the krausen change or pressure ferment change, but you'll definitely know that ferment is done.
For a wine ferment though which just seems to bubble away with no krausen at all the offset seeems bang on.
However I wouldn't stop using my hydrometer for a final check before packaging.