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An experiment that is baffling me

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Gggsss

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Afternoon all...

Bit of a strange one here (well for me anyway). I may be experiencing my first stuck fermentation.

Basically I started my 4th brew on Sunday 17/01. It was a simple pale ale recipe but brewed two 9L batches, one with 1.2kg of DME and one with 1.5kg of LME (simple test to see if LME is the culprit for the dreaded twang). Same volume of water, weight of steeping grains, hops, timings, temperatures for pitching (used US-05, 1 pack each batch) and fermenting etc. Basically the same conditions. They both had the same OG of 1.048.

By the next morning the LME batch seemed very lively with lots of airlock activity, whereas the DME batch's activity was more modest (it was slightly active but about 70-80% less activity than the LME). I checked to make sure both lids were tight (which they were). I didn't worry about it and have just monitored it. During the week it has been the same. So today curiosity got the better of me and i took the readings. The DME was/is 1.015 (which I was very surprised by due to the lack of activity) and the LME was/is 1.012. Both readings seem acceptable to me after just 3-4 days. I'm just concerned that the DME has stalled. Just wondered whether DME ferments slower and both will be around the same in another 10-15 days (when I usually bottle - after 2 to 3 weeks in the FV).

Just a bit confused really (which aint hard)....

Any thoughts??????
 
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Hazelwood Brewery

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Leave them going and don’t worry about them for at least another week. Airlock activity is nice to see but completely useless as any form of measure.

Have a little faith (and a little patience).
 

Gggsss

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Hi Hazelwood, thanks for the reply. I really appreciate it...

I'm aware airlock activity isn't a true reflection of progress (hence the DME gravity drop with little activity) but why would the readings be different if the same recipe, OG, yeast, temps etc??? I'm hoping they finish within a couple of points of each other and am happy to wait. Just wondered if any particular "science" to the differences...

So by the looks of it, it's not a stalled batch...

Cheers...
 

An Ankoù

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Afternoon all...

Bit of a strange one here (well for me anyway). I may be experiencing my first stuck fermentation.

Basically I started my 4th brew on Sunday 17/01. It was a simple pale ale recipe but brewed two 9L batches, one with 1.2kg of DME and one with 1.5kg of LME (simple test to see if LME is the culprit for the dreaded twang). Same volume of water, weight of steeping grains, hops, timings, temperatures for pitching (used US-05, 1 pack each batch) and fermenting etc. Basically the same conditions. They both had the same OG of 1.048.

By the next morning the LME batch seemed very lively with lots of airlock activity, whereas the DME batch's activity was more modest (it was slightly active but about 70-80% less activity than the LME). I checked to make sure both lids were tight (which they were). I didn't worry about it and have just monitored it. During the week it has been the same. So today curiosity got the better of me and i took the readings. The DME was/is 1.015 (which I was very surprised by due to the lack of activity) and the LME was/is 1.012. Both readings seem acceptable to me after just 3-4 days. I'm just concerned that the DME has stalled. Just wondered whether DME ferments slower and both will be around the same in another 10-15 days (when I usually bottle - after 2 to 3 weeks in the FV).

Just a bit confused really (which aint hard)....

Any thoughts??????
It's a great experiment and it seems to be showing some results. So why should there be a difference? Were both samples from the same manufacturer? It may be that different malts were used or the circumstances of the mash prior to concentrating the wort were different. If they were from the same stable, it may be that the degree of concentration has an effect on the makeup of the fermentable sugars or the nutrients in the extract. There's no reason to think the DME version has stalled until you get the same gravity reading over a number of days.
I'm not an extract brewer, but this thought occurs to me: is it the case that LME is meant to used instead of grain in a recipe, while DME is considered to be an additive, but a better one than white sugar? If that's the case, it may well be that LME is mashed to contain more unfermentable, longer-chain sugars to give more body, while DME is designed to be more fermentable. Of course, If my premise is wrong then what follows is complete nonsense.
 

Gggsss

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Hi An Ankou. Thanks for the reply. Facts and nonsense, all welcome..

I suppose that may be the case, different manufactures for the two types of extract (in layman's terms).

Both were pale/light (so the same type/style in their form). As for the intended uses, as far as I'm aware they have the same use in each form. Both can be used in place of grain or sugar. Basically both are your main fermentable when used in this way (again this could be a load of old waffle)....

As of now I'm taking it as "it is what it is". And no need to pitch more yeast, sugar etc and leave it be (unless anyone thinks I should take particular measures)...
 

umfana

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...

As of now I'm taking it as "it is what it is". And no need to pitch more yeast, sugar etc and leave it be (unless anyone thinks I should take particular measures)...
Wouldn't taking any measure on one sample and not the other invalidate your experiment? If you then detected "the twang" in one and not the other you would not know if it was due to the measure you took or if it were the original variable.

Good experiment tho.
 

Gggsss

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Hi Umfana. Thanks for the reply. - It would indeed invalidate the experiment but was just thinking the lesser of two evils so to speak. My theory was just salvage (although I'm less concerned now). My thinking was different gravity would display different levels of wort sweetness so would impair the comparison significantly. Whereas a small amount of a fairly natural flavored yeast and/or sugar (to get the DME moving in the direction of the LME) would have just a negligible impact and would result in staying truer to the intended experiment.

This is all just me assuming. It's only my 4th brew and the first without using some kind of kit. And using individual ingredients. Long story short, I'm winging it (don't have much technical knowledge yet)
 

Clint

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Liquid and dry malt have different levels of fermentables..I'd need to get my notes to confirm the ratio...
 

An Ankoù

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Liquid and dry malt have different levels of fermentables.I'd need to get my notes to confirm the ratio...
Liquid malt contains about 20% water and dry malt about 2% moisture. so the ratio would be 80/98 or liquid malt is only 0.816 as fermentable as dry. Or 98/80 so dry extract is 1.225 times as fermentable as liquid. Roughly 80% and 120% respectively.
But that's only if my sums are any good.
 

Gggsss

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Cheers all....

Yeah as mentioned above I factored the difference. I set it up as close to each type as possible. As mentioned both had the same OG, just wondered why one is fermenting faster and/or further (not sure of the latter yet but not worried now).

I really appreciate everyone's input
 
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