High attenuation help.

[JohnB]

Hi folks, I've done several brews with all grain starting out with the basic recipe on here. I have made some lovely stuff, but I have a question about my latest batch which seems 'Odd'. I decided to do a brew with GP and a little light crystal to make a lightly coloured English Bitter and to do something that I could mow the lawns and have a pint, then carry on gardening without falling over, so aiming for about 3.5% ABV.

Everything went well; or so I thought until the end of fermentation, well, it is still ticking over after 11 days! We are now down to 1003 and still bubbling. I know you can't really tell just what a brew will be like until it is properly finished by tasting it from the FV. However, this is really dry - as would be expected at 1003.

OG was 1036, [it was 1034, but I added a little light syrup to up it to 1036] I fermented at 20 DegC and the aim was to go to about 1006 - 1008. The hop aroma is really lovely and a quick taste suggests a nice bitter flavour with orangey overtones that would be expected: but it's the really really dry finish I'm a little worried about as it will leave the beer thin and watery (I think). This is 18 litres and to that I used 1oz Fuggles at 60 min and 1oz Challenger at 5 min.

I have used Bulldog B4 (Hambleton Bard).

Do I leave this to continue? Do I rack it off now? Will a weak beer like this condition better? I'm beginning to understand what is meant when people say it's difficult to get decent body and mouthfeel in a light ABV beer.

 

[JohnB]

Sorry I meant to add "Thanks for any help or suggestions" but hit return before I go that bit down.

 

[Zephyr259]

You generally want a beer to be completely done before you do anything to it and secondaries aren't really required so there's not much to do other than leave it for a few more days and see where the FG stabilises at. It's weird you've gotten over 90% attenuation, but I'm not familiar with that yeast, still even saison strains often need help getting that high.

If it tastes fine then you are unlikely to have an infection. Maybe yeast just go crazy sometimes? My current batch of Wyeast 1728 Scottish Ale performs as expected and gives about 71% average attenuation, but the first pack i got 2 years ago gave me 86% attenuation which is quite a common occurrence for that strain it turns out.

 

[Sadfield]

Sounds like a classic saccharomyces diastaticus contamination to me. Infections don't necessarily result in off flavours.

Have you previously brewed using a dry Saison yeast?

 

[Zephyr259]

Sounds like a classic saccharomyces diastaticus contamination to me. Infections don't necessarily result in off flavours.

Have you previously brewed using a dry Saison yeast?

I thought diastaticus strains took a long time to break down the dextrins so they were more of an issue in bottling? If not then that does sound most likely.

 

[The Baron]

What temp did you mash at as a low mash temp will aid attenuation

 

[Sadfield]

I thought diastaticus strains took a long time to break down the dextrins so they were more of an issue in bottling? If not then that does sound most likely.

I think it depends on the level of contamination, low level contamination in commercial brews may only present a problem after bottling, however a large pitch of a Diastatic strain like Belle Saison will break down dextrins pretty quickly. They excrete amylase to outside of their cell structure, so very much like mashing and fermenting at the same time, making simpler sugars, from any starches and dextrins, available to the pitched yeast.

 

[JohnB]

Hi Guys, I have no idea what a erm ... diasticky thingy is, I take we are talking a strain of wild? yeast, or a yeast that is (we had a Saison beer in our local a couple of months back - excellent stuff!). Anyway, @Sadfield No, I haven't brewed using that Saison yeast. I'll give a bit more detail below, I keep spreadsheets (sad, I kno0ooow) of each brew. @the baron My strike temp is 80 DegC or just below, then this gives me a mash at 66 DegC - 67 DegC and this fell to 62 DegC over the hour, but I use a brew-belt, so the mash toward the outside is a little warmer and I recorded 64 DegC around the outer edge of the mash tun. I stirred everything up just once during the mash to even out the temp, so if we say: Max T was 67 DegC and min at the end of mash (60 minutes) was 62 DegC, they are the outer extremes. The boil was 60 mins and everything was cooled within 40 minutes to 22 DegC and the yeast pitched dry into the wort, FV sealed and left then until I started to get worried that fermentation seemed to go on too long (still slowly bubbling after 11 days). That's when I took my 1003 SG reading and came on here for a bit of help. Incidentally, I have time tomorrow to take another sample and if the SG has not dropped appreciably below 1003, I think I'm going to bottle and see what happens.

Right I'm off to have a look at this Saccharomyces diastaticus yeast now and do a bit of reading, so thanks for this. I'll report back tomorrow if I detect disaster on its way when I have another look in the FV - it's still sealed up at the moment and a slow bubble about every minute to 1-1/2 minutes now, I'll be back. Thanks all.

I've used this yeast before in a very similar brew (slightly heavier with OG of 1048) to this one and it finished at 1009, so, Zephyr, probably some kind of wild yeast? I'll have another taste tomorrow.

 

[MyQul]

What sort of 'syrup' did you add? If it was some sort that is almost pure sugar (eg golden syrup), in such a low OG this would possibly acount for your low OG as the yeast can chop it's way through all of it lowering the FG to what you would expect if it was just grain only

Another factor to take into consideration is an overpitching of your yeast. 1.036 is quite a low OG and if you pitched a whole packet of yeast, this is really an overpitch as a packet of yeast has absolutely loads of yeast cells in it, more than enough to ferment out a batch with OG 1.060. So an OG of 1.036 will be made short work of . Overpitching can cause over attenuation.
I also like low OG session beers and usually make my beers to about the same OG (1.037/1.038). I normally use the Gales strain of yeast which on higher OG beers usually gives me 75% attenuation. However I usually ere on the side of caution and overpitch. Which normally results in some sort of overattenuation My last beer of OG 1.036 using the Gales strain hit 80% attenuation.

Combining this overpitch with the syrup may well have got you down to such a low FG

 

[Sadfield]

Some very good points there @MyQul. Another symptom of over-pitching is usually a very fast fermentation or worst case, stalling if the yeast flocculates too quickly. Although I'm not totally sure more yeast cells will result in a strain being able to digest complex sugars they normality don't.

 

[MyQul]

Although I'm not totally sure more yeast cells will result in a strain being able to digest complex sugars they normality don't.

That's what I sometimes wonder as I've definatley witness overpitched yeast overattenuating lots of times. Perhaps with a correct pitch the yeast dont consume all the sugars they're able to and leave some unfermented. But with an over pitch they consume absolutley all the sugars they are able to?

 

[JohnB]

Hi MyQul, you may have hit the nail.

'Syrup' was pure sugar. I make my own 'golden syrup', basically it is a light caramel mixed with partially inverted sugar - sugar boiled for a while with a tiny amount of citric acid and then mixed to the right colour. However, all I wanted was to boost the OG by a couple of points without altering the colour, so this was 'white' syrup, partially inverted sugar - just a mix of fructose, laevulose, and glucose really, without the caramel. So I guess it would ferment fairly well! I can just picture the yeast going: "Ohhhh yummmmy!"

Second, this was only a 20l brew, so a packet of yeast in a 20l brew? at low OG? The yeast was slow to start though, it took a couple of days for the airlock to start bubbling.

I have used this yeast before, it's top fermenting, but it has always formed a nice compact yeast cake on the bottom of the FV after fermentation is complete. This time I have big clumps of creamy yeast floating in the wort, some on top, some on the bottom and some just hanging around in the liquid.

It really doesn't "feel" right, and the taste is a bitterness bordering on acidic that hangs in the back of the throat after the bitterness of the hops has gone. There's also a slight acidic - but not unpleasant smell - on opening the FV. Trouble is this is not a good test at all because after a 3 or 4 weeks conditioning the taste can change so much.

Thanks for that idea though.

 

[MyQul]

All that yeast floating around in you're beer certainly sounds like their much more in their than really needed

 

[JohnB]

Today is IT! I am going to get this into a secondary, try to transfer as little yeast as possible. On opening the FV there was a slightly acid smell, not unpleasant, but a there was a 'whiff' about it - is this acetyl? A quick taste was inconclusive, dry finish, bordering on thin, a nice bitterness that kind of hangs in the back of the throat, but no sweetness and no mouthfeel, no real body. This was sort of expected of this ale, but just not the silly ultra-dry finish and the 1002 FG.

Once the FV is empty and I have some time I'm going to do the same brew again, halve the yeast, watch the mash temp and up the grain slightly so I don't have to add any sugar to reach my target of 1036 - 1038.

Thanks for all the replies, and if anyone has anything to add, I'll be watching along. Later, 2 or 3 weeks or so, I'll come back with some thoughts on the final beer. I'm not holding out any hopes on this one and it may find it's way out to the North Sea a bit quicker than intended!

 

[MyQul]

For my 1.037ish beers I mash at 70C and only for 40 mins. They never taste thin and dry doing this even if I get 80% attenuation

 

[The Baron]

I think from the answers you have got the answers. A mash that has dropped to 62 ish will make the beer attenuate more plus overpitch of yeast and as Mcqul has explained more in depth the sugar solution just like honey will make the yeasties chew threw it. the answer is mash higher temp and as Mcqul is pretty much a expert of lower gravity beers do 70c as advised with less yeast and no sugar solution aswell maybe a little more grain to substitute this

 

[ACBEV]

I think you should try a different yeast too. I love a few old fashioned watery bitter when gardening in the summer.

Mine normally finish around 1.007 - 1.008 from 1.035-6, approx. 3.5% and I also use some invert syrup, usually 200g. But not had a fall to 1.002. I start my mash at 66c and raise the temp to 72c in a few increments over 60 minutes.

 

[JohnB]

All the above makes perfect sense, and as you can tell I'm home today with buggerall to do! (apart from ) so a sample under the microscope shows Lactobacillus infection at perhaps a few percent of the yeast population - don't ask what species, I haven't a clue and I'm not going down that road but L. brevis is common in beer at this temp. The beer is now in a secondary and apart from a slight acid taste is clean and so I think I'll let it carry on. Heaven knows what I'll get, but hey ho, being new to this game its all experience.

So for my next go it's mash higher and less time, try another ale yeast (I have some CML English Ale Yeast), and I think, I may use a bit more grain as well. AND I'll be a bit more careful with the yeast as well, there was more than an inch of slush in the bottom of the FV and big clumps of flocculated yeast floating around throughout the wort.

Thanks, everyone for your input, I just thought I'd done something dramatically wrong, which it turns out it was several things, really. Again, thanks all

Time for another.

 

[Sadfield]

Unlucky. Although it may turn out into something interesting. Could be the base of a fruit beer as a last resort.

Also, jealous of the microscope, especially one capable of picking out bacteria.

 

[bobukbrewer]

for a 3.5% beer use 8 lb of pale malt in 21 litres of water, mash at 71-72 deg C for 60 minutes then after the hop boil chill down to 20 deg C as fast as you can - mine usually stops at 8 or 9 BRIX