High Fg - Consistently

[Goose]

G'day boys.

Tell me wtf I am doing wrong please. Last 4 AG ales I have not been able to drop below 1.020 FG. Am using a grain bill of 5 kg and water: grist ratio of 3:1. Mashwater strike is usually bang on 75 deg C and I end up with a mash temp of around 66 deg C +/- 1 degC. Mash for 1 hour and batch sparge with water at 75 deg C to give me a 27 litre boil yielding just over 23 litres of wort. I machine aerate (paint stirrer), and pitch at around 22 deg C, ferment at 16-17 deg C. I also add 1/2 tsp yeast nutrient to the boil, I might add.

Have tried 2 different yeasts , Premium Ale and English Ale from Craftbrewer and fermentations have started beautifully and gone gangbusters for 3 days or so, then seem to immediately stop at around SG 1.020-1.022. At first I thought it may have been an excessively flocculant yeast or too low a temperature but have tried shaking, stirring and raising temperature to 20 deg C, no effect, SG stays where it is even if left in primary for 4 or 5 days after shaking her up.

Taste is pretty good, surprisingly not too sweet and hops bitterness comes through nicely, but clearly the beer has big body, dont mind it but I am actually trying to achive a dry ale style. :huh:

Been thinking through all the variables and can only think I'm preparing my wort somehow thats coming out with too many unfermentables but did not figure that a mash temp of around 66 would be so dramatic given I've read others at this temp can get down to 1.012 pretty easily. So you can see why this is giving me the irrits but at least my problem is consistent.

Have taken a read of this link but not alot of joy.

Your ideas welcome please.

 

[tangent]

all i can suggest is to try a mash at 64-65C and ferment at 18-20C. 16C may be a little too cold for your ale yeasts at the end of fermentation.

 

[Jye]

Goose, I had this problem for a few of my beers turns out my thermometer was out by about 3C and my mash temp was up around 69C. If you have already checked your thermometer did you check it in a ice slurry and in boiling water? My thermometer gave a correct reading in the ice slurry but read 94C in boiling water :angry:

 

[Adamt]

Could be your hydrometer out, try testing it with tap water and it should measure around 0.998, though if as you say is quite heavy on body, it might not be that.

I assume you've checked your thermometer after reading the thread so that's out of the picture. Hope you didn't actually shake the fermenter, oxidation here we come!

 

[bigfridge]

G'day boys.

Carefull mate, there are girls here too don't forget

Am using a grain bill of 5 kg

What malt are you using ?

Dave

 

[Hogan]

Hi Goose

What have been your OG readings of the wort going into the fermenter. It may be that your hydrometer is crook.

16-17c is a low ferment temp for ales unless you are using US-56 or similar that is specifically set for low temps, but you also say you have tried raising the temp with no noticable restart. How long after they kick off do you drop the temp down to 16c.

Cheers, Hogan.

 

[user 384]

The most likely culprits are:

1. Grain bill - too high a % of crystal malts leaving loads of unfermentables
2. Thermometer out - leading to a too high mash temp and a dextrinous wort
3. Hydrometer out - your beer is fine, but your hydrometer is reading too high

Cheers
MAH

 

[Goose]

Carefull mate, there are girls here too don't forget

really ?

What malt are you using ?

Standard Pale Ale. Not sure of its source but its used by a local microbrewery that outsells some of its grain to homebrewers.

Hydrometer, tested that , 1.000 with water... thermometer... its a digital probe type, not had a basis for comparison yet between 0 and 100 deg C but its a possibility.

Temperature of fermentation, yes I agree my fridge probably too cold but while the fermentation is happening its extremely vigorous. When, after 3 days I remove the fermenter to a warmer place ie around 20 deg C I get no further SG fall. btw adam, no real shaking, more like a swirling motion (all sealed) just to try to get some of the yeast back into suspension.

Think u guys are convincing me its the mash temp thats my problem. Putting down an amber ale this weekend and I'll report back... thanks for the suggestions.

Goose

 

[dreamboat]

I would recommend that you have a better go at aerating the wort - or pitch more yeast. You can aerate up to 24 hours after pitching, but personally I draw the line at around 12 hours. Give your brew another run with the paint stirrer ( assuming that it entrains plenty of air, not just stirring the brew - now that I think about it, a paint stirrer would be designed to not entrain any air!!) at least on one more occasion within that 12(ish) hour window.
Mash pH may also be worth a look for a general improvement in your beer, particularly if you are not using much in the way of dark grains.


Rob

 

[Justin]

All good advice so far. Thermometer accuracy is well worth checking.

Also, might be worth your while to find out exactly what malt they are using. It could be a very dextrinous malt that the brewery normally cuts with some sugar to pull the FG down a bit. Some of the older malts (not sure how much is used these days) such as Schooner etc were very dextrinous and that is a large reason why the mega breweries added a high % of cane sugar.

I don't have experience using malts like galaxy, barret burston, schooner, franklin etc-does anyone know what these malts are like in regards to dextrins? I've only used JW, Hoepfner, TF, Weyermann all of which are quite nice malts well suited to all malt beers. Anyone else with some thoughts?

 

[stephen]

For aeration of my worts, I now use a whisk - the type with all the wires - and run it between my hands like trying to start a fire without matches. Just have half to two thirds of the bulbous part of the whisk in the top of the wort and go for it. It only takes a couple of minutes to have it foaming up. When it does this I then vigourously stir the wort with my mash paddle until the foam drops considerably and also to mix aerated wort with non aerated wort. Repeat generally up to three times depending on wort.

I've also used this method with just the mash paddle - using only the flat part in the wort - with good success as well.

Cheers

Steve

 

[Screwtop]

Sounds exactly the same as my recent problem. Last brew I checked my thermometer against two good expensive ones. My brewing thermometer gave a mash temp of 65C, the two others read 69C. So when mashing at 66C the temp has actually been 70C. Took temp of my grist before mashing, brewing thermometer 20C others 24C, no wonder my strike temps have been out. Have two brews in the fermenter as I type, one mashed hot and the other at a tested 65C. The hot mash stopped bubbling the airlock (US-56) after 2 days, the wort mashed at a true 65C is still going like crazy (US-56) after 2 days. Check your efficiency into the boiler, mine has increased with lower mash temp.

That would be my guess, aeration is more to do with getting a good start for your culture. I would also look into the malt and how much Crystal etc, but for my money its hot mash.

 

[Goose]

Sounds exactly the same as my recent problem. Last brew I checked my thermometer against two good expensive ones. My brewing thermometer gave a mash temp of 65C, the two others read 69C. So when mashing at 66C the temp has actually been 70C. Took temp of my grist before mashing, brewing thermometer 20C others 24C, no wonder my strike temps have been out. Have two brews in the fermenter as I type, one mashed hot and the other at a tested 65C. The hot mash stopped bubbling the airlock (US-56) after 2 days, the wort mashed at a true 65C is still going like crazy (US-56) after 2 days. Check your efficiency into the boiler, mine has increased with lower mash temp.

That would be my guess, aeration is more to do with getting a good start for your culture. I would also look into the malt and how much Crystal etc, but for my money its hot mash.

V. good information thanks Screwtop. Doubt the issue is grain related, though in my last brew I did use 250 g of carapils + 250 g Amber, I doubt this is sufficient enough to cause the issue. Going to be doing some tests tonight on my thermometer.

 

[tangent]

"250 g of carapils + 250 g Amber"
that's a truckload more than i'd use

 

[Ross]

goose,

I'm sure you'll find the answer in the ideas above - for what it's worth, my money's on mash temp as well - dried yeasts don't require much (if any) additional oxygenation & it sounds like your brews are all getting off to a good start...

cheers Ross

 

[Ducatiboy stu]

I to suffered High FG readings and found out my thermometer was 3*c to high. That one is now in the bin

 

[Justin]

I to suffered High FG readings and found out my thermometer was 3*c to high. That one is now in the bin

Throwing it out is a little unnecessary given you know it's 3 degrees out. Mark it or stick a label on it so you know which one it is and then always add 3 degrees to the reading. Most thermometers aren't that accurate as we are all finding out here. I have a couple of lab ones that seem to be pretty good but my digital is 1.3 C out.

 

[Ducatiboy stu]

Labels and marks come off to easly when continually put in hot water and grains.

It gave me a good excuse to but a better thermometer.