High FG question

[Borneogoat]

About 3wks ago I brewed my first AG batch in many years. I did a SMaSH of:

12# Maris Otter
1oz Cascade @ 60/20/5min
Mash for 75min @ 66.7C
Target OG = 1.054
Actual OG = 1.050 with about 21L into the fermenter
Pitched WLP0028 at ~ 17.8C, 1.5L healthy starter, target FG = 1.012
Note: no pH testing or conversion testing during mash, didn't wanna play with H2O chemistry until more experienced.

I kept my fermenter at a steady 17-18C for the first week. Airlock started burping along between 12-24hrs later. Bubbled from Day #2 till Day #4 and then paused. Day#5 SG was 1.030. Day #6 she started bubbling again. Around Day #8 weather got cold and fermenter fell to ~14C at night. Bubbling stopped, SG = 1.023. I brought it back up to a steady 20C and held there since. Day #14, SG = 1.023, pitched some SA-05 & yeast nutrient hoping to kick the action back up, bubbling occurs. Day #20 (today) still SG = 1.023.

So I've concluded FG isn't going to drop below 1.023, because 2wks steady. Still a little airlock activity, bubble every 5-10min. Gonna bottle tonight, because it doesn't appear to be dropping and the hyrdo samples taste sweetish but drinkable.

What happened here; why the high FG?

I didn't test pH or starch conversion during the mash. The local water (Hobart) is quite soft. I added a bit of gypsum, but that's it. If my pH was high, might I have had poor conversion and thus too many unfermentables in my wort? Or something else?

Next batch is tomorrow, but now I have a pH meter and iodine....

 

[antiphile]

Hi mini goat

Gotta admit even with a single step mash like yours I'd be guessing an FG 1.012 to 1.014 off the top of my head. I'm assuming the starter was healthy with sufficient viable cells and within use-by dates (are you happy to assume that too?)

Things I'd check:
1. Is the mash thermometer reading the correct temp? (within a degree should be OK)
2. Was the wort well aerated or oxygenated at pitching?
3. Is the ferment thermometer reading correctly? (I see WLP028 doesn't ferment well below about 17C - but it should recover well if you gently rouse the yeast and have it at a true temp of 19C or a touch over. If you have the facility, you can resuspend the yeast using carbon dioxide or nitrogen but follow sanitary practices).

To be honest, I'm guessing number 1 is the problem in combination with a non-uniform temp across the whole of the mash tun.

 

[dannymars]

also check your hydrometer in water (should read 1,000 @ 20C). I have one that is 4 points out on the high side.

 

[Yob]

Mash for 75min @ 66.7C

this is certainly a contributing factor, some time spent in the lower temperature range can help make a more attenuative wort, still 1.023 is quite high

 

[Borneogoat]

1. Is the mash thermometer reading the correct temp? (within a degree should be OK)
2. Was the wort well aerated or oxygenated at pitching?
3. Is the ferment thermometer reading correctly? (I see WLP028 doesn't ferment well below about 17C - but it should recover well if you gently rouse the yeast and have it at a true temp of 19C or a touch over. If you have the facility, you can resuspend the yeast using carbon dioxide or nitrogen but follow sanitary practices).

To be honest, I'm guessing number 1 is the problem in combination with a non-uniform temp across the whole of the mash tun.

These are things I considered too. I think I'm ok on mash temp. My system is a Brew Boss and it recirculates thru & during the entire mash, so temps should be quite even. I checked the temp sensor against a Thermapen and it is less than 1F different, so I'm ok here too. The fermenter is a Brewbucket with FTSs and has solid temp control. I've check temp calibration here too. The one night the ferment got cold, went from needing chilling at bedtime to needing heat while I was asleep. The FTSs can do both, but only one at a time.

However, your comment about aeration could be something. My aeration was poor. Tried the aquarium pump trick and it didn't work well, not powerful enough pump I think. I've grabbed an O2 bottle system for next time. That said, I did pitch a second round of yeast and raised the temp to around 20C. Would this second pitch be hindered by the original poor aeration?

I checked the hydrometer in tap water and it seemed ok too. But I didn't check it in a wort on known SG. I'll make a fairly exactly measure mini wort with DME and test this possibility.

Would high pH result in poor mash conversion and leave me with this high FG? Or am I barking up the wrong tree?

 

[Borneogoat]

this is certainly a contributing factor, some time spent in the lower temperature range can help make a more attenuative wort, still 1.023 is quite high

Oops, a conversion typo. I mashed at 154F/67.8C, rather than 152F/66.7C. So this would indeed result in more unfermentables. I get the impression from the many recipes that I've read over that 154F/67.8C is fairly common for a beer with some body. Should still be able to go lower than 1.023, right?

 

[danestead]

I mash my apas at 68 and the fg is usually down around 1.012-1.014ish. I dont think your mash temp is the problem. If ph was a problem with conversion, I would have thought you would have got a low OG. I dont 'think' ph affects the fermentability as much as you have achieved. Do you have a water report? Is your calcium very low? Also, not that ive done it, but dry yeast is reported to not need oxygenation, so I dont think your lack of aeration/oxygenation would be a factor post pitching the us05 dry yeast.

Sorry I dont have any solutions.

 

[mje1980]

Oops, a conversion typo. I mashed at 154F/67.8C, rather than 152F/66.7C. So this would indeed result in more unfermentables. I get the impression from the many recipes that I've read over that 154F/67.8C is fairly common for a beer with some body. Should still be able to go lower than 1.023, right?

Yeah, should still go lower than that. Is that London ale yeast?

 

[mje1980]

Ah the Scottish yeast. Should still have come down further I think.

 

[Borneogoat]

I wondered if the WLP0028 Edinburgh yeast might be the problem. The internet is full of stories about slow ferments and this yeast. That's why I tried a second pitch with US-05 dried yeast a week ago. Afterwards, lots of bubbling but no SG drop. Which I'm confused by...

I don't have a current water report, but a report from 2013 listed Hobart as:

Alkalinity CaCO3- 9mg/L
Calcium - 5.11mg/L
Calcium Hardness - 128mg/L
Chloride - 6.4mg/L
Magnesium - 1.08mg/L
Magnesium (Dissolved) - 4.4mg/L
Sodium - 3.89mg/L
Sulphate - 3.6mg/L

Now I'm still learning how to play with water chem, but my LHBS suggested some gypsum and that sounded about right. So I added 8g/2tsp gypsum to my total water volume (mash + sparge) of about 32L.

To test the pH question, tomorrow's brew recipe includes about 2oz of chocolate malt and 4oz acidulated malt. Both of which should lower the pH and I'll test with my shiny new pH meter.....

 

[danestead]

I wondered if the WLP0028 Edinburgh yeast might be the problem. The internet is full of stories about slow ferments and this yeast. That's why I tried a second pitch with US-05 dried yeast a week ago. Afterwards, lots of bubbling but no SG drop. Which I'm confused by...

I don't have a current water report, but a report from 2013 listed Hobart as:

Alkalinity CaCO3- 9mg/L
Calcium - 5.11mg/L
Calcium Hardness - 128mg/L
Chloride - 6.4mg/L
Magnesium - 1.08mg/L
Magnesium (Dissolved) - 4.4mg/L
Sodium - 3.89mg/L
Sulphate - 3.6mg/L

Now I'm still learning how to play with water chem, but my LHBS suggested some gypsum and that sounded about right. So I added 8g/2tsp gypsum to my total water volume (mash + sparge) of about 32L.

To test the pH question, tomorrow's brew recipe includes about 2oz of chocolate malt and 4oz acidulated malt. Both of which should lower the pH and I'll test with my shiny new pH meter.....

That water report calcium is very low. Im not sure what your calcium would of been after the gypsum addition however a few texts recommend a minimum of 50ppm. Im lead to believe some yeasts like more than others though.

As for your ph meter, you may well be full bottle on how to use them but if not, they can be quite a complex bit of equipment. The main bit, is to cool your wort sample to room temp (20-25ish degrees) before testing the ph as ph changes with temperature. You will still need to cool it even if your meter has ATC (auto temp correction). ATC corrects for errors in the meter, not chages of ph in your wort with temperature. Also, calibrating each day before brewing will ensure the best accuracy.

Enjoy.

 

[Borneogoat]

Mashing now for my next brew. Tried the iodine test at 10/20/30/45mins. No black tinted reaction! So I've either got no starch at all (not likely!) or the iodine is not the right stuff. Using Betadine Antiseptic Liquid with 10% Povidone-Iodine = 1% available iodine. Anybody used this stuff or suggest something that works better?

 

[technobabble66]

Hey goat. How did the original batch turn out?

Fwiw, I've had a batch of MJ Dark Ale stall at ~1.022, sit there for ~2 weeks, then fire back up and go like crazy. So my advice would be if it's stalled quite high, just leave it until the yeast wakes up again - can take a few weeks.

Also, fwiw, I've got an Irish Red going ATM with WLP028. It blew out the top 3 times at the start - took off like a beast. But only slowly been dropping the SG. It's roughly been taking off 2 points per day, maybe 3/d for the first few days. I had it at 19*C for the first 2 days but after the 2nd blow-out I dropped it to 18 for 24hrs to slow it down. By then, it'd dropped maybe 10-13 points in 3 days. Well it def slowed down - almost stopped. So back up to 19 and it went to this 2 points per day thing. So I cranked it to 21*c to speed it up (hoped to bottle it by Friday this week. No chance now [emoji34]). And it still just chews out 2 points per day.
V annoying, but OTOH it's tasting fantastic.
The tricky thing is this is meant to be a "starter" batch to prep a yeast cake for a wee heavy. So now I'm a little concerned the yeast isn't going to be able to do the job and stall early. Basically I think I'll wait and see. If it's a bit of a tortoise and steadily keeps chewing 2 points per day I'll go with it, just allow for a long fermentation. If it slows down even more I might see what else I can do.

 

[antiphile]

Mashing now for my next brew. Tried the iodine test at 10/20/30/45mins. No black tinted reaction! So I've either got no starch at all (not likely!) or the iodine is not the right stuff. Using Betadine Antiseptic Liquid with 10% Povidone-Iodine = 1% available iodine. Anybody used this stuff or suggest something that works better?

Betadine is definately not what you want. Try this from BYO:

The iodine test is one way to determine whether there is any residual starch that lacks conversion. Just head to the local pharmacy and pick up a “tincture of iodine.” This is a small bottle that will last you about 10 years if you do not knock it over while performing the test.
It comes with a small dropper attached to the cap that allows you to lay a drop or two into a shallow sample of cool mash on a white dish. Be sure no grain material is present; this will yield a false positive. If the iodine color ranges from yellow to amber, conversion is complete. If the iodine turns dark purple to black, give the mash another 15 minutes and repeat the test. If a conversion is not reached after two hours, check your mash temperature. You may have undershot the target conversion-rest temperature.

 

[Borneogoat]

Hey goat. How did the original batch turn out?

It turned out pretty good. Yes, still a bit on the sweet malty side, but enjoyable. I got myself some lab grade hydrometers and discovered the homebrew grade hydrometer was drastically out. About 0.004 points and not a linear offset. Correct SG readings should help in the future! I've also improved my grain crush, added oxygen at pitch, and a heap of other tweaks. They cumulatively have helped, because my currently fermenting batch of Janet's Brown Ale is at about 1.017 now.

Betadine is definately not what you want. Try this from BYO:

Yep, I found some iodine tincture now and tried it on my last batch. Seemed to work just like your suggested method.

I've got a second fermenter on the way, so it should be a happy Xmas of brewing!