High FG

[Jolls]

G'day Punters
I have ad dilemma that I trust someone with more experience can assist me with. I have two beers int he fermentation fridge - A 1931 Tooths White Horse Ale clone based on the recipe in Bronzed Brews and a Vanilla Milk Stout. The calculated OG/FG for the pair was 1.052/1.008 and 1.047/1.011 respectively. The Stout went down a week after the The White Horse Ale.

The OG into the fermenter for both was 1.044. Yeast Safale English Ale S-04 yeast pitched at 19C. The Ale fermentation appeared to stall at 1.017 and the Stour at 1.020

I swirled them and raised the temp to 22C for a week - no change.
I added additional S=04 yeast and could small the carbondiaxide being relaeased. Five days later curring gravity readings remain at 1.017 amd 1.020 respectively.

Water is rainwater and I have yet to do an analysis of it. I did not check the PH level as I have had no problems with any of my previous brews. something I must do in future.

The Stout has 150g of lactose tht ws added to the boil.

Any thoughts on why the FG is so high?

Plan is to crash and keg it this weekend (subject to the wsdom inparted here)

Thanks in advance fro your guidance.

Cheers n Beers

Jolls

 

[MHB]

Ok, assuming you made 23L of wort the Lactose will have added around 0.0026 to your FG. Given how hard it is to read an Hydrometer to four places that probably accounts for the extra gravity in the stout.

If the White Horse went from 1.044 to 1.017 you have an apparent attenuation of (44-17)/44=61%, well under the 75+% you would expect from S-04.
The most obvious place to look is at your mash temperature. Have you calibrated your mash thermometer, odds on its out and you mashed hotter than expected, making more unfermentable dextrins than intended.
Been saying for a long time that every brewer should have a decent quality Lab thermometer that they use to check everything else, especially dial thermometers.
Mark

 

[Jolls]

Ok, assuming you made 23L of wort the Lactose will have added around 0.0026 to your FG. Given how hard it is to read an Hydrometer to four places that probably accounts for the extra gravity in the stout.

If the White Horse went from 1.044 to 1.017 you have an apparent attenuation of (44-17)/44=61%, well under the 75+% you would expect from S-04.
The most obvious place to look is at your mash temperature. Have you calibrated your mash thermometer, odds on its out and you mashed hotter than expected, making more unfermentable dextrins than intended.
Been saying for a long time that every brewer should have a decent quality Lab thermometer that they use to check everything else, especially dial thermometers.
Mark

 

[Jolls]

Thanks Mark
I paid particular attention to the mash temperature but I can't vouch for the calibration of the thermometer. I was concerned that the temperature was dropping too quickly in the esky I use as a mash tun. I added boiling water to bring it back up to temp at the 30 minute mark for both brews. I have just purchased a robobrew so trust I will have better control for the next brews.

So my next steps in building my system and knowledge base should be:

Lab thermometer
Water test

I guess it is now a matter of keging and enjoying what I have and brewing it again down the track to se if I can make a better version. Taste out of the fermenter for both brews is good so I expect the end result to be enjoyable despite the dissapointing FGs.

Cheers n Beers
Jolls

 

[MHB]

My local sells a good glass Lab thermometer for $15. Just be a little careful when you select one. They range from complete crap to ridiculously precise and expensive (say $400), somewhere in between is a good call.

If you look after it it will last a lifetime and is a great investment.
Don’t know where you are located or who you get your stuff from, but choose carefully and it will serve you well.
Mark

 

[Jolls]

Hi Brainstrust,

Need a bit of help based on the wisdom of more experienced brewers.

I took Marks advice and purchased a good thermometer. Threw down the next brew and was super vigilant with the temperature in the new Brewzilla 4. Had the brew in the fermenter for 10 days SG 1.034, and there it has remained for the last three days. Target FG is 1.008. For the life of me I couldn't figure out the problem. Took a reading this evening 1.034 - so I took out the old Coopers Hydrometer and low and behold reading 1.011. So I look back and the high FG correlates to switching from the trusty floaty hydrometer to a handheld ATC. Has anyone come across this before?

Probably no issue with the previous brews either - they taste great out of the keg and have the right effect so I guess the hand held was the problem all along.

I will recheck the calibration of the handheld hydrometer but in the meantime taking one step backwards and reverting to what I know.

About to start my first lagering process!

I'll let you know how I get on.

Cheers n Beers

Jolls

 

[MHB]

Well if you used a Refractometer once the ferment has started that would be the answer.
How a Refractometer works is it measures how far the sample bends light. Water bends light (refracts it) a certain amount, Alcohol a different amount and Sugars another set of different amounts. Brewing refractometers are all calibrated against white sugar (admittedly wort is slightly different but not much). Basically a 10% W/W (i.e. 100g Sucrose 900g Water) solution of sugar in water will be 10 Brix or Plato, it will have a gravity of 1.040 (or very close)
As you ferment, sugars mainly Maltose, converts to Alcohol and CO2. You end up with a three part problem, you can calculate the Gravity but it requires mathematic manipulation of the numbers. There are plenty of online calculators and a few good explanations of the equations they use if you want to understand the process better. Play with a couple and find one you like, you have the numbers to hand to plug in. Makes using a Refractometer pretty easy and they are convenient for quick checks.
Mark

 

[Jolls]

Thanks Mark
You are a lifesaver. Take two days off next weekend!

A definite lightbulb moment for me. I had wondered about the how the refractometer compensated for the "dirtiness" of the brew and rationalised that it was measuring the light refraction from the sugars. I assumed that the calculator worked the same post fermentation but did not account for the difference between sugars and alcohols. It did not dawn on me until yesterday that the high FG readings only started when I changed to using the refractometer.

I plugged the details into a calculator and it correlates with the calculated SG. Same for the two previous brews. So it had nothing to do with my technique (although the lab thermometer tip has certainly improved my process). As a tradie the old adage that a poor tradesman blames the tools is always in my mind. I went straight to thinking my process was bad as opposed to the readings from the tool I was using. It is not that the tool was bad - just the tool taking the readings was didn't educate himself well enough.

This has taken a load off mind. I am enjoying my Vanilla Milk Stout more now that I know it turned out right! Amazing that a change in mindset can change how you feel towards an inanimate object like beer.

Cheers n Beers

Jolls

 

[livo]

This is probably a good place to ask. Is it ready to bottle in glass.

I used a can of the NZ Beermakers brand Old Beer with 1 kg of Milk Stout blend (LDME DDME and Maltodextrin). The instruction on the can says it should finish at 1.006 using brewing sugars. It is my understanding that the maltodextrin will add some points (40 ppg) of unfermentable dextrin but I don't know how much was in the 1kg bag. It looked like it was mainly the malt extracts. Maybe 200g of white.

Anyway, it's been fermenting at 22'C for 10 days today, which is fine but, I took a gravity reading on Friday, day 5. It was 1.016. On Monday (day 8) it was still 1.016. Yesterday it was again 1.016. I called the HBS guy on Monday and he felt I should leave it go to about 1.010 since I'm bottling in glass. I agree, but I'll bet it hasn't moved again today. I did a rough calculation based on 40 ppg, assuming 200g (6.5 oz) of MD in the mix and 6 gallons of liquid and I get about 2.5 to 3 points, which would be what the HBS guy said and it should finish at around 1.010. This is not near the 1.016 I seem to have finished at.

The airlock is in equilibrium with atmosphere and doesn't produce a burp when I touch the lid of the FV. However, the samples taken off to read gravity are bubbly and heady and the froth takes a while to fade. So, is it ready to bottle?

 

[yankinoz]

Which yeast? Did you do anything to raise or stir up the yeast?

 

[livo]

Hi again Yank. Thanks for asking.

It was just the supplied yeast that comes with the Beermakers can, so I'm not really sure of exactly what it is. I asked at the HBS guy if a different yeast would be better, and he said the supplied stuff was OK. He didn't take the opportunity to sell me anything extra, which is appreciated. I would have bought it if advised of significant improvement. This beer is for a mate who doesn't have room to do his own. I don't normally make dark old beer although I never used to mind drinking it occasionally. (I remember when 50s were very popular.)

I have done nothing to the FV since the yeast was pitched by simply sprinkling on the surface after topping up with water to the 23 litre mark, so, no I haven't done anything to raise or stir up the yeast. Should I? I've never done anything before. The water used was well oxygenated and free of chlorine, but I don't know the full chemistry of it. It's never been a problem of this type before.

The temperature range for the yeast is 18'C to 28'C and I'm at 22'C so just under mid-point. HBS guy said on the phone that this was good, preferable actually, to be on the cooler end, but it might take longer than specified (5 - 7 days to reach 1.006). That's all fine but I didn't expect a complete stall for 5 days with what is apparently at least 6 points to go. I'm not expecting 1.006 because of the MD content.

Edit: I have 2 FVs with "Lager" cans going that I started 2 days after the stalled one and they are finished today and ready to bottle. So, this is day 10 for the Old beer which is still sitting at 1.016 and the "Lagers" will be down to nearly 1.000 after 1 week. Different beer I know, so not really comparable.

 

[mblwest]

I would bottle it, clearly it has stopped. Could simply be more unfermentable sugars, maybe a quality control issue? Another thing you could try is raising the temp to 25 or 28 to see if that encourages the yeast to kick in again.

 

[MHB]

The yeast is probably Mauri 514, its not bad, just what comes with the kit is a bit on the small side. The Home Brew Shop guy selling you a better (bigger) yeast would have been doing you a favor.

Its really hard to know where a beer is going to finish if you don’t know three things fairly accurately
1/ The Volume
2/ The OG
3/ What you put in the brew.

When someone says "Milk" that almost always means its got Lactose (milk sugar) in it, Lactose is totally unfermentable so whatever is added has adds to the FG.
Malt extract is around 65% (give or take) fermentable, the remaining 35% (ish) adds to FG.
Most of the weight of Maltodextrin you added will still be in solution adding to FG.

The kit with 1kg of dextrose would finish at or around 1.010 assuming you made it to 23L, you are at 1.016 so you have about 350g (0.350kg) more in solution than you would if you used fully fermentable sugar.

Its done, bottle it, but it’s a good idea to cut the bottle priming down a touch, big black beers taste better at a lower fizz (mostly) and there will be some slow fermenting sugars in the brew that will add a bit of fizz over time. Big Black beers tend to age well and tast best around 3-6 months old, some even older (personal opinion).
Mark

 

[livo]

Thanks guys. I've had to go back to the HBS today and got to speak with the boss man, and his son again, which is who I spoke with earlier. The Maltodextrin is 250g so there is 750g of LDME and DDME combined. I was again informed it should finish at around 1.010, which is in line with my rough estimates. I hadn't considered unfermented components of the malts so I guess that will add a point or 2. On Monday I suggested the possibility of raising the temperature slightly, but he advised me to leave it go a bit longer. When I said today that it has now been stable for 5 days at 1.016 they suggested now trying to give it an extra 1 or 2'C for a day or two to see if it goes anywhere. Old mate said two weeks to ferment it is perfectly normal, but I just don't understand the stall for 5 days.

Now the update: I was a step ahead of them and myself when I posted this morning. Yesterday afternoon, I lifted the temperature by only 1'C to 23'C and when I've just been to the shed for the first time today, nearly 24 hours later, I again have positive outward pressure in the airlock (not surprising as temperature could do that), but it has dropped to closer to 1.015, so it is still slowly fermenting.

I tend to agree that it is done, but I'll give it until tomorrow anyway. I will take your advice Mark and prime on the light side. It will be bulk primed, and it is 23 litres in volume. I usually use 150 - 160g for 30 - 32 X 750 ml, but with it being still a bit bubbly in the FV I'll probably reduce to 100g.

Thanks for your help. I'll keep the thread informed of the progress and outcome.

Edit: I was wrong to call it the Milk Stout Blend. They do have that, and it does indeed have Lactose. What I used does not and it is their Creamy Stout Pack with Maltodextrin.

 

[livo]

There is now no doubt in my mind that it is done. It's not going to reach 1.010. I bumped the temp up another degree yesterday to 24'C. No change! Even my reading of 1.015 yesterday is dubious as I'm reading 1.016 again this morning. The big difference is that yesterday it was gassy, with a head on the measuring cylinder. Up to and including yesterday, it has actually been taking me a few minutes to get the gas bubbles off the hydrometer and allow the head to disappear before reading.

Today is has come out of the tap nearly flat. Very tiny gas bubbles this time and no head foam at all. As short spin and twirl plus a few pushes and the hydrometer settled right on 1.016. So, it's 11 days in the FV and 6 days at the same gravity and she's cooked. Bottling this afternoon.

I've got 2 more cans of the same beer concentrate and I've also bought another bag of the malt / maltodextrin but I also bought a different bag which is malt and dextrose. I'll do a the next one with the dextrose and it will be interesting to see how far it gets down and how long it takes.

 

[philrob]

After reading posts like this for the last 16 years, I don't think I've ever had anyone comment that their FG was ever down to what the kit instructions say. In my very early brewing journey I never managed it. I reckon they may well deliberately state the FG lower than what is realistically achievable, particularly with inadequate yeast quantities supplied with the kit, and so the lawyers have a defence and can blame the punter when someone is injured by a bottle bomb. Maybe I am now getting too cynical in my old age, but I'm only stating my own observations. Anyone have a different experience?

 

[livo]

Well, my usual crappy lager tins usually ferment right out (or pretty close anyhow), but I haven't been using anything fancy. Just dextrose, light malt powder or the Coopers Brew Enhancer or no name substitutes. I can usually get them down to between 1.000 and 1.003. Certainly, within the green bar on my hydrometer. As I said, I don't normally do heavier dark beer so maybe this is what to expect. Perhaps if you use refined white cane sugar, they'll go all the way (aimed at the mug punter I suppose). The tin label said 1.006 and I reckoned 1.010 or thereabouts. But it has well and truly stopped above that and it's going no further.

Edit: Next day. I didn't get to bottle yesterday due to unforeseen events. It will be bottled today and if it is still reading 1.016 then it will have been on the same reading for 1 week. Actually, today is day 8 counting last Friday. This would mean that the yeast essentially fermented the brew in 4 - 5 days and it has sat "cleaning up" for 7 - 8 days. The big thing of note here is that yesterday it was a lot flatter and so I feel more comfortable about bottle priming it. A few bubbles have never bothered me but this one just seemed to still be quite gassy for a long time even though the gravity wasn't changing.

 

[yankinoz]

After reading posts like this for the last 16 years, I don't think I've ever had anyone comment that their FG was ever down to what the kit instructions say.

A classic case of negative evidence. Why would reaching the recommended FG move anyone to inquire why it happened? But your other points are well taken

 

[livo]

Well perhaps this may help somebody explain what has happened, not that it really matters, but it would be interesting to know if it's explainable at all.

First off, it was still 1.016 this morning and it is now in bottles. To be exact it is in 35 X 650 ml glass bottles with each containing approximately 635 ml. This means that with what I had left over, my 23 litre mark on the FV is a bit low (500 ml or the thickness of the permanent marker line). My calculation of what I added with the priming sugar and what I removed in the test tube (6 times) plus that left in the FV with the yeast cake, is that I started with approximately 22.500 litres, not 23. So that's the starting volume.

Next up is the Creamy Stout Pack. I have another and it would appear to me that is contains 500g Dark Malt, 250g each of Light Malt and Maltodextrin. Other than the full can of Beermakers Old concentrate, that's all that went in, and that was on Monday morning, 20 Feb.

I looked at my notes on the removed label and I did actually measure the OG, which was 1.048. This was done prior to pitching yeast, which as already mentioned earlier, was the supplied pack.

This morning it was bulk primed with exactly a scraped level half cup of white sugar, ie; 115g, weighed on the scales and easy to replicate. I would be more than happy for somebody to do the math and tell me if 1.016 is where it should have finished, after really only 4.5 days. There she sat steady until this morning. Today is day 12 but it has been 11 full 24 hour days from pitching yeast to priming and bottling. I can only assume that my hydrometer reading, where I said 1.015 was a faulty reading on my part.

Temperature was held at 22'C for 9 days and increased by 1'C and then another 1'C on day 10 where it sat until I bottled today on day 12.

So, it dropped 32 points, and I then added approximately 5.2 g of sugar / litre. Estimated ABV =????

 

[MHB]

There is nothing complicated or unexpected going on.

Your OG is clearly off. Specific Gravity (SG) is the density of stuff in solution (solids) plus the water it is dissolved in as compared to the weight of the same volume of water. SG and Plato (oP) can be applied to tell us the amount in solution. Conversely if we know the volume and what we put into solution we can predict what the SG/oP will be.

The basic equation is
Mass in solution = Volume*SG*oP

You added a 1.8kg kit which is 80% solids, so 1.44kg. Another 1kg from the bag of dry mix so 2.44kg.
If your volume is 22.5L and you play around with the equation that relates SG and oP
SG= (4*oP)/1000+1
Well the easy way is to shove the whole thing into a spread sheet and use Goal Seek

Your OG was 1.0416, which is a fair way from 1.048.
Most common mistake is to have some heavy syrup in the tap that is then flushed into the hydrometer tube giving a false high OG.

If you want to get a pretty good idea of the alcohol content we can just take the change in points and divide by 7.5.
If you want to include the priming sugar you could just add it to the original mass (2.44+0.115=2.555kg) and shove that back into the spreadsheet to calculate what the total change will be (remember that the sugar won’t change your FG (1.016)).

I get 1.0435, take away the 1.016 and we get 27.5 Points so the ABV would be ~3.67% ABV

It’s a good rule of thumb that if you don’t hit FG in 7 days you have underpitched! You got there in about 3 days, no surprise really considering it’s a pretty light beer (should taste good, best in about 6 weeks+)

Might be a good idea to watch a you-tube or have a read up on how to use an hydrometer properly.
Mark