Higher OG and lower FG?

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tomdhuggon

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Hi all, quick intro - first post, second brew, umpteenth time on the site, infinite appreciation of your brewing wisdom. Thanks - you've helped so much already.

With my head spinning with all the variables and slightly giddy (read- tipsy) from the success of my first kit brew - a 23L NZ pale ale kit - I've cracked on with a Coopers Innkeepers Daughter sparkling ale kit using additional DME and dry hopping (cascade, 50g).

I originally wanted 20L so used 1kg of DME (as opposed to 1.5kg for 23L). However, a couple of concerns:
1) LME got all clumpy and try as I might to stir through, I added it to only-tepid water. I wonder if this will have affected OG.
2) Regardless of point 1, the OG came out at around 1.050 - way higher than anticipated and would have given ABV of 5.7% had the FG reached 1.006 as expected.

I topped up with additional water to 23L and OG read 1.040.

Question is - having added additional water should I still expect the FG to reach 1.006? Or will it end a little higher (1.010)?

As ever, I anticipate the answer to be "give it a couple of weeks and see" but just curious as to how this will have affected FG and whether "higher OG=lower FG".

Thanks!
 

MickDundee

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Yeast attenuation is a percentage. A yeast with a quoted attenuation range of 77-80% will munch through 77-80% of the sugars. A beer with a 1.050 SG with this yeast will finish at about 1.010 whereas a beer with a 1.040 SG will finish at 1.008.

I’d be surprised if you were getting the 88% attenuation required to take the beer from 1.05 to 1.006 with a kit yeast if I’m being honest, especially if you’ve used DME instead of sugar, but I don’t do kits so I might be wrong.
 

tomdhuggon

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Hi @MickDundee , thanks for the quick and insightful answer! That's really great information.

What factors affect attenuation? I imagine different yeasts have different ranges. But does volume of yeast also make a difference? If you doubled the amount of yeast, would you reach a higher % attenuation?

I think my brain might be too curious for brewing. I'm going to end up getting sectioned for thinking/talking about it too much.
 

terrym

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Attenuation is a characteristic of that particular strain of yeast. Some are better at it than others. Its like their ability to flocculate.. And some yeasts are more alcohol tolerant than others
Next my experience with Coopers kits is, if you used the kit yeast (irrespective of the fact that there is not a single yeast covering all their kits) and the OG was in the range 1.040 to 1.045, you are unlikely to go below 1.008, and 1.010 is more likely.
Finally the BF calculator below says that if you used 1.7kg LME kit can plus 1 kg of DME to 20 litres your OG would have been 1.042, diluting to 23 litres OG would have been 1.037. And basically it cant be anything else, or if your sample reading was otherwise , your wort was not homogenised.
 

MickDundee

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Hi @MickDundee , thanks for the quick and insightful answer! That's really great information.

What factors affect attenuation? I imagine different yeasts have different ranges. But does volume of yeast also make a difference? If you doubled the amount of yeast, would you reach a higher % attenuation?

I think my brain might be too curious for brewing. I'm going to end up getting sectioned for thinking/talking about it too much.
Using a good amount of healthy, rehydrated, dried yeast means you are more likely to hit the top end of the yeast’s attenuation, but as @terrym says, attenuation is a characteristic of the yeast so you won’t suddenly create a beer that ferments to 1.001 because you’ve used 5 sachets of yeast.

The problem with kit yeasts is that they tend to give you 5-7g which is borderline enough in most cases, whereas the sachets of dry yeast that the HBSs step are usually around 11g which is a good number for a 1.040-1.050 beer. This is the reason your kit yeast is less likely to hit the top end of the quoted attenuation range.
 

tomdhuggon

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Finally the BF calculator below says that if you used 1.7kg LME kit can plus 1 kg of DME to 20 litres your OG would have been 1.042, diluting to 23 litres OG would have been 1.037. And basically it cant be anything else, or if your sample reading was otherwise , your wort was not homogenised.
Hmmm this is interesting. Maybe the heavier extract was still on the bottom and meant my reading was a bit off? I tested the hydrometer just before and it gave a reading of bang on 1 for just water, but I did take a reading quite soon after I added the water.

Either way, assuming 1.037 OG and 80% max attenuation, does that mean I'm looking for a FG of 1.008 (rounded up)? Got a reading after 4 days in the primary and it was 1.012 so could be on track for that.
 

tomdhuggon

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The problem with kit yeasts is that they tend to give you 5-7g which is borderline enough in most cases, whereas the sachets of dry yeast that the HBSs step are usually around 11g which is a good number for a 1.040-1.050 beer. This is the reason your kit yeast is less likely to hit the top end of the quoted attenuation range.
Thanks @MickDundee that's really helpful to know. I've located my most local HBS in South London, but going to have to make a list as it's about a 45 minute cycle away so can't forget anything! I'm aiming for 3/4 kit brews then moving to extract, but want to get a rough handle on the science/process first.
 

terrym

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Thanks @MickDundee that's really helpful to know. I've located my most local HBS in South London, but going to have to make a list as it's about a 45 minute cycle away so can't forget anything! I'm aiming for 3/4 kit brews then moving to extract, but want to get a rough handle on the science/process first.
Crossmyloof sell a good range of yeasts and hops plus other stuff here, and are used by many forum members. There's also a small forum discount.
Personally I have never really had a problem with Coopers yeasts. Unlike Muntons supplied kits they usually ferment out, and don't get stuck.
And rather than 80% attenuation my experience of kits and their yeast is the attenuation is usually in the lower 70s. For me that's not a bad thing since I don't want my beers dried out since I prefer to have some sweetness left in there.
 

tomdhuggon

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Thanks for your resposes! Really appreciate the input - will definitely check out Crossmyloof and pay more attention to attenuation in future.

My final question for this thread - it looks like I'm looking at a slightly weaker than preferable brew at this stage - maybe between 3.6% and 3.8% depending on attenuation.

I'd prefer it to be above 4% - what's the potential risk of putting an extra 200g of brewing sugar in? Enough to slightly increase the ABV but not so much that it dilutes the flavour. Or should I try and get my hands on some more DME?
 

Wynne

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With a 200g addition the difference between the two would be marginal. Personally, I would suggest finishing the brew you already have in fermenter and use that as a baseline for assessing future brews, changing only one variable at a time to assess the impact.
 

tomdhuggon

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Hi @Wynne , I'm inclined to agree. Will update on here in a few weeks to let you know how it went down! Should be perfect for a hot summer evening.
 

Sadfield

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Using a good amount of healthy, rehydrated, dried yeast means you are more likely to hit the top end of the yeast’s attenuation, but as @terrym says, attenuation is a characteristic of the yeast so you won’t suddenly create a beer that ferments to 1.001 because you’ve used 5 sachets of yeast.
You could. Over or under pitching affects attenuation. The percentage ranges given are not absolutes they are guides based on the assumption brewers pitch the yeast at an appropriate rate.
 

terrym

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Thanks for your resposes! Really appreciate the input - will definitely check out Crossmyloof and pay more attention to attenuation in future.

My final question for this thread - it looks like I'm looking at a slightly weaker than preferable brew at this stage - maybe between 3.6% and 3.8% depending on attenuation.

I'd prefer it to be above 4% - what's the potential risk of putting an extra 200g of brewing sugar in? Enough to slightly increase the ABV but not so much that it dilutes the flavour. Or should I try and get my hands on some more DME?
If it matters you will get about 0.2 % addition from the priming sugar. Personally I'd leave it as it is. I'm sure the difference in ABV at the values you are discussing is barely detectable by taste.
Then next time with your lessons learned you will have a better chance of getting it closer to what you require.
 

tomdhuggon

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UPDATE

So, for anyone still interested I took @terrym 's advice and decided not to add any additional sugar and see how it played out. I dry hopped with the 50g Cascade as planned.

After 15 days in the FV, I went to bottle. To my surprise the hydrometer reading was 1.005. (Attached photo.) I tested the hydrometer in water and it was bang on 1. I took another sample from the FV and got the same result.

If OG was 1.037 and FG was 1.005, does this mean an apparent attenuation of 86%? Is that possible with no additional yeast other than what was provided in the kit? Does dry hopping affect attenuation at all?

(As a side note, the hop pellets didn't sink to the bottom as I'd expected. The photo shows a couple of floaters. Managed to filter most of them out but it was a real PITA. Will be trying the bag next time!)
 

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Horners

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Might be a trick of the light but it that is your FG sample looks higher than 1.005?
 

tomdhuggon

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@Horners yeah sorry not the best quality pic but the water level is sat between 1.004 and 1.006. The water level was on 1 for the water.
 

tomdhuggon

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@Ezza ruddy marvellous! Learnings below from this which was brew number 2:
1) I think the high OG was a result of the water/malt not being properly homogenised - I might have taken the reading too early. FG finished up at 1.006
2) Pellets are messy but so far the best way of extracting hop flavour (also tried the strainer method). I dropped them in with no bag, hence the messyness. Have tried with a mesh bag since and worked much better from a clean-up perspective
3) Bottling bucket is necessary.

Have done 6 brews in total so far.
 

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