Slow Burn Then Rocket Ferment

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phoenixdigital

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Ok this is an odd one and I am really only posting to find out what people think has happened here.

We have just made our first all grain with this recipe
http://www.aussiehomebrewer.com/forum/inde...amp;recipe=1299

I made a starter from the white labs vial with 1 cup of LDME and 1 litre of water about 3 days before making the wort.

We mashed at what we thought was 66 deg and followed everything from there. We only had a 19 litre pot and a 10 litre pot so we split the wort up between the two. Used less lautering water to make sure it would fit in the pots we have. Only added the hops to the larger pot.

Cooled as quickly as possible with ice and a bit of 5 deg cold water into fermenter to top up to 23 litres.

We ended up with about 1.070 which is pretty close to the recipe. Even though the recipe was for 25 litres. We deliberately put less water in knowing efficiency would probably be low.

We could only get the wort down to 37 degrees so couldn't pitch until the next day after it had been sitting in the fermenting fridge at 20deg for 20 hours.

After pitching the starter I checked the SG about 3 days later. It was still at 1.070!!!! I checked it twice. There appeared to be a krausen as well that had subsided.

We thought one of a few things might have happened after some googling
1) Yeast was dead
2) Mashed too high and had too many unfermentable sugars
3) Not enough oxygen in the wort

So we committed a sin and opened up the fermenter and gave it a massive stir to mix in some oxygen in the hopes that would start her up.

Now 24 hours later it is 1.010 SG..... WHAT???? Measured that twice as well. Doesn't taste any different to previous either.

There is a lot of sediment in the SG vessel (prob from stiring 25 hours ago) could that be affecting the SG measurement?

Is it possible that when we measured the 1.070 SG that there was a layer of unfermented wort on the bottom of the fermenter and the wort above it was almost fully fermeted.

Anyone have any idea what happened?

I am not too worried as the beer still tastes good. Just want to know where we might have gone wrong.

Hopefully the big stir lastnight didn't add too much uneeded oxygen into the wort. Will this screw it up?

So many questions...
 

ekul

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Will this screw it up?
If it tastes good then it probably IS good.

I reckon the yeast were building in numbers and then when you oxygenated it gave them a boost.

Which yeast was it? Was it san diego super yeast? I've noticed that yeast does nothing for a few days and then finishes really quickly.
 

phoenixdigital

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If it tastes good then it probably IS good.

I reckon the yeast were building in numbers and then when you oxygenated it gave them a boost.

Which yeast was it? Was it san diego super yeast? I've noticed that yeast does nothing for a few days and then finishes really quickly.
Thanks for the response. The yeast was White Labs WLP001 - California Ale

I was worried that oxygenating it might introduce bad flavours as they always say to be careful of splashing (introducing oxygen) when racking and bottling.
 

Jace89

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You must of measured it wrong or something, doesnt make sense to me. Maybe there was something like unfermented wort or something but the odd have got to be slim/impossible.
I'd try to answer your questions but I gotta get to bed, just thought I'd make a post so you don't loose any sleep lol.
But if I was you I wouldn't be worried about it, after all the beer is tasting great right?
 

phoenixdigital

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You must of measured it wrong or something, doesnt make sense to me. Maybe there was something like unfermented wort or something but the odd have got to be slim/impossible.
I'd try to answer your questions but I gotta get to bed, just thought I'd make a post so you don't loose any sleep lol.
But if I was you I wouldn't be worried about it, after all the beer is tasting great right?
Yeah its a weird one. Thats why we measured twice.

As mentioned it tastes good so not overly concerned.

So for future reference if someone happened to mash at say 72 deg. Would ALL the sugars created here be unfermentable or only a percentage?

I was thinking that we might have mashed too high and the yeast had nothing to work with.
 

phoenixdigital

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What did you use to measure? Hydro or Refractometer?
Same hydro for both and measured at the same temp too.

The refractometer is next to useless I have found. Might be good when doing all grain in a full size kettle.
 

brettprevans

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Same hydro for both and measured at the same temp too.
.
you used a top fermenting yeast, took a sample from the bottom of the fermentor and wonder why your SG reading is high?..... do you understand what im getting at?

if you doubt what im insinuating, think about what happended when you stirred the wort/beer up? you got a lower SG reading as they wort was mixed and gave a more accurate reading as there were no pockets of higher density wort. now yes sediment can play a role but you should have been able to tell what your sample looked like. if it looked liek the yarra obviously the sample is full of crap and going to be a false reading. if its pretty clear then the sediment wont be playing much of a role.

im also not sure why you'd other checking SG after 3 days for a 1070 wort. sno way it would be done. but thats neither here nor there, excep that the yeast will ferment slower in growth phase (which 3 days is probably still growth phase in a 1070 beer).

Same hydro for both and measured at the same temp too.

The refractometer is next to useless I have found. Might be good when doing all grain in a full size kettle.
this statement puzzels me to no end. refract is so much better than a hydro but they both do a similar thing. its makes no diff wheteher its AG or kits a refrac does exactly the same thing ie measure light coming thorugh the liquid and thus density of liquid.

PS yes im aware fermentation for both lager and ale yeasts takes place in suspension and the top or bottom more refers to where it settles. my point probably should have been that heavy wort falls to the bottom more and lighter wort sits on top. thats just fluid dynamics. so you took a reading with more concentrated wort which was diluted with less concentrated wort once you stirred it up.
 

phoenixdigital

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you used a top fermenting yeast, took a sample from the bottom of the fermentor and wonder why your SG reading is high?..... do you understand what im getting at?

if you doubt what im insinuating, think about what happended when you stirred the wort/beer up? you got a lower SG reading as they wort was mixed and gave a more accurate reading as there were no pockets of higher density wort.
As you can see from my first post that is what I suspected but it is good to get confirmation thanks.

refract is so much better than a hydro but they both do a similar thing. its makes no diff wheteher its AG or kits a refrac does exactly the same thing ie measure light coming thorugh the liquid and thus density of liquid.
Maybe my refractometer is crap (ebay) as its measurements are nowhere near as accurate as the hydrometer. If anything they are nowhere even near what we read with the hydro. The line is a solid blue with water at zero. Then when measuring beer its a fuzzy line around the SG mark it claims (which doesn't match hydro readings)

The reason I mentioned all grain was that they are supposedly better for quick measurements of your wort during the boil/mash as the sample cools quickly and you can get a reading fast. Hydrometer requires adjustments for temperature and a much greater sample size.
 

doon

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If you are using refrac during fermentation you need to use tools in beersmith to adjust readings

I use my refrac at all stages now so much better and only need a tiny sample
 

brettprevans

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Maybe my refractometer is crap (ebay) as its measurements are nowhere near as accurate as the hydrometer. If anything they are nowhere even near what we read with the hydro. The line is a solid blue with water at zero. Then when measuring beer its a fuzzy line around the SG mark it claims (which doesn't match hydro readings)
hmm maybe. have you tried adjusting the focus? im assuming you have. in which case it might be the refract. or make sure you clean the refract glass surface well. i see your point now that you've said u cant get an accurate reading. i dont have that problem with mine but i bought it off Craftbrewer. digital refrac would be better than normal refrac and hydro but is expensive.

so long as your beer has turned out well its all ok.

oh and gently shaking the fermentor around (or sriwling or whatever), is ok. its a trick to help try and get yeast back into suspension and help stuck fermentations. bribieG? i think and a few others swear by oxiginating wort after 72 to help ensure a healthy ferment and without any oxidation or negative side effects. so your beer is probably fine
 
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