Over attenuating

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Jeltz69
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Re: Over attenuating

Post by Jeltz69 »

Recently there was a thread on one of the forums about thermometer accuracy where the poster found his to be 6° out and the bit of paper inside a hydrometer can slip if there is a jolt.

Both of these are easy to check, so I would still eliminate them as variables before throwing away FV's and so on.

You could also check the airborne yeast theory with a Petri dish with wort and agar. If its that prevalent a short exposure in the area you boil/chill will infect the agar/wort mix and provide a strong yeast culture on the plate.
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SandyM
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Re: Over attenuating

Post by SandyM »

My hydrometer has the lines painted on so I don't think it's that. I will test it anyway though. Same for the thermometer, seems unlikely it would be that far out but again worth testing.

I have 8 FVs as I tend to buy new ones every year or so, the 2 I'm using atm I bought in January and I'm pretty careful with cleaning with a plastic brush. Again worth testing although I get the exact same reading from both FVs. I suppose it is possible as they have been giving lower FG for a while and something could have got into both but again, same problem through several different ones.

The ball lock is a good idea, it's something I tend to overlook on the basis that its attached to the boiler and so should heat up in the boil and kill off any nasties. I spray star san up the spout before running out but there is no harm dismantling and giving it a thorough cleaning just to be sure.

Might give brewing in another spot a go and see how that works out too.
Burns stuff. And makes beer. Usually not at the same time.
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vacant
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Re: Over attenuating

Post by vacant »

SandyM wrote:I spray star san up the spout before running out but there is no harm dismantling and giving it a thorough cleaning just to be sure.
A good clean is reassuring. How about getting two sterilised-to-buggery glass bottles. Dip one in the wort to fill, fill the other from the tap. Ferment both alongside your FVs. If they all finish low it's airborne.
When a man is tired of beer, he is tired of life; for there is in beer all that life can afford
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steve crawshaw
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Re: Over attenuating

Post by steve crawshaw »

How are you chilling? Immersion? IMO going to a plate chiller was one of the best decisions I made. You can autoclave or boil it so you KNOW it is sterile and it just saves so much time and hassle. If you're not using silicon hose, start. Again, this can be autoclaved or boiled.

When you are leaning over the boiler waggling that copper coil around in the cooling wort all sorts of detritus (nothing personal!) will be coming off your clothes, skin, hair etc. Call me paranoid but when you've ditched as many batches as me you become ruthless about contamination sources.

However, I cannot believe that any live organism can remain viable on the ball valve of a boiler that is sat at 100C for >1 hour.

cheers
steve
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PMowdes
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Re: Over attenuating

Post by PMowdes »

You're probably right Steve, it's just that i took my ball valve apart last time i brewed (for the first time i might add) and it was full of vinegary beer which probably got between the ball and the housing, dispite me cleaning it quite well.

I'm not saying that something like that would be a source of infection but it's not worth taking the risk.
60 percent of the time it works every time.
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SandyM
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Re: Over attenuating

Post by SandyM »

steve crawshaw wrote:How are you chilling? Immersion? IMO going to a plate chiller was one of the best decisions I made. You can autoclave or boil it so you KNOW it is sterile and it just saves so much time and hassle. If you're not using silicon hose, start. Again, this can be autoclaved or boiled.

When you are leaning over the boiler waggling that copper coil around in the cooling wort all sorts of detritus (nothing personal!) will be coming off your clothes, skin, hair etc. Call me paranoid but when you've ditched as many batches as me you become ruthless about contamination sources.

However, I cannot believe that any live organism can remain viable on the ball valve of a boiler that is sat at 100C for >1 hour.

cheers
steve
I've had to ditch my fair share of batches making my pretty paranoid too. I dunk my immersion in 15 minutes before the end of the boil and then lift it out after cooling very carefully from the side. Not saying nothing falls in but anything that did would be minimal.

Besides, this all sounds like infection prevention, surely an infection isn't the issue here?
Burns stuff. And makes beer. Usually not at the same time.
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SandyM
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Re: Over attenuating

Post by SandyM »

vacant wrote:
SandyM wrote:I spray star san up the spout before running out but there is no harm dismantling and giving it a thorough cleaning just to be sure.
A good clean is reassuring. How about getting two sterilised-to-buggery glass bottles. Dip one in the wort to fill, fill the other from the tap. Ferment both alongside your FVs. If they all finish low it's airborne.
Might try that next time.
Burns stuff. And makes beer. Usually not at the same time.
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