FG seems incredibly low...

[biggtime]

Hi guys,

Quick question - I've just taken a gravity reading of my beer, having left it in the fermenter for 8 days (I was away on holiday so had to leave a few things to chance), and the reading seems to be as low as 1002. Target final gravity was 1010. Has something gone wrong? Is my hydrometer lying? Or has the yeast been more efficient than I expected and the beer will be 'stronger' than expected? I didn't think final gravity usually got as low as that.

 

[PD]

is your hyrometer reading correctly ? check it in plain water at the temp its calibrated for...should read 1000

 

[joe1002]

I have had beers ferment to that. What yeast are you using?

 

[biggtime]

Thanks both. Just checked the hydrometer with water, and it may indeed be incorrectly marked. Or I'm just reading it wrong. The water reading (admittedly the water was a little cold) seemed to be about 6 points below the beer reading. That being the case, perhaps the beer is actually somewhere around 1008, which seems more likely. The yeast was White Labs WLP023 Burton Ale Yeast. I did pitch it reasonably warm (around 24 degrees C) and the fermenter stayed at about 22 degrees C the whole time, so I understand that can push things a little harder. It's also been in there for 8 days. But perhaps it is just the hydrometer?

 

[Asalpaws]

If it's AG brew you might have had the mash temp low, tends to make the wort more fermentable, also adding sugar tends to make for a low FG. Wouldn't have expected an Enghlish ale yeast to go so low but certainly some of the Belgian strains can get your beer very dry! T

 

[biggtime]

I reckon it must be a faulty hydrometer, to be honest. Tried the beer straight from the fermenter and it is tasting pretty drinkable already, and not too strong at all, so it all seems to have gone well. It should be a hoppy best around 4.1% or so, and at a guess I'd say it wasn't much more than 4%. I suppose the only issue is that if the hydrometer is faulty then I also don't really know what the OG was for sure. I thought it was 1.040, but who knows. Next item on the shopping list, proper hydrometer instead of a cheapie!

 

[biggtime]

Afternoon all. Not sure what the etiquette is for continuing a discussion, but I'll try posting here and see if that helps. I've just experienced a similar 'issue' again today - an FG that seems lower than it should be. Got myself a new hydrometer after the last fiasco, and took an OG reading with that which came out spot on 1.040 (which was the target OG) once I'd added a couple of litres of water. It's had 10 days in the FV, took a good 24-hours to start fermenting initially, and I've just taken a reading with the new hydrometer. Target FG is 1.010 but this time I've come out somewhere between 1.006 and 1.007 (adjusting for the temp of 18 degrees would bring it closer to 1.006). So it's second time in a row, with pretty much the same recipe and same yeast (White Labs WLP023 Burton Ale yeast). Is my yeast just being exceedingly efficient?

 

[Pinchy]

Remember that the temperature of the beer & water have an impace on the hydrometer reading. I thought i had a faulty one until i realised that i was measuring water much colder than my hydrometer was calibrated to. Mines calibrated to 21°C.

 

[biggtime]

Remember that the temperature of the beer & water have an impace on the hydrometer reading. I thought i had a faulty one until i realised that i was measuring water much colder than my hydrometer was calibrated to. Mines calibrated to 21°C.

Yep, taken that into account. The beer being measured for FG was 18 degrees C. It's a 20 degree hydrometer. So worryingly, that drops the FG even further, closer to 1.006. Not a disaster, just not sure what's causing it!

 

[biggtime]

Just read around on this a bit further, and at the moment, things are pointing towards the mash heat as part of the issue. Only thing is, it never says how/why that causes a problem. Mash temperature was pretty much bang on 66 degrees C, as intended. And after 90 mins had only dropped by 0.5 degrees. How can that cause a problem when it seems to have gone to plan?

 

[keith1664]

Are you sure your thermometer is accurate? If the mash temp was too low then you can end up with a more fermentable wort and hence a lower FG.

 

[biggtime]

Are you sure your thermometer is accurate? If the mash temp was too low then you can end up with a more fermentable wort and hence a lower FG.

Accurate as far as I can tell. I'll give it a couple of tests.

 

[Asalpaws]

Other factors might be pitch rate, are you adding a massive starter of yeast? That can give more attenuation. T

 

[pittsy]

Have you set your attenuation of the yeast used in your software ? It may be set slightly high for that yeast , It may just be a fraction better that stated , water quality can make a difference , sounds like your's is good . If you wish it to finish fuller try mashing warmer like 68c .

 

[biggtime]

Other factors might be pitch rate, are you adding a massive starter of yeast? That can give more attenuation. T

Not as far as I can tell. Just one of these: http://www.brewuk.co.uk/store/ingredien ... lp023.html at room temp. Says it is right amount for 5 gallons.

 

[Dr Mike]

Based on a few reviews around the net, it seems as though quite afew people find wlp023 to be more attenuative than the Whitelabs spec suggests.

I've just done a 1064 bitter with it which finished up at 1015 which is 77%.