Fermentation Concerns

[Mercs Own]

Further to my trials with my wheat beer I put down last week;

http://www.aussiehomebrewer.com/forum/inde...showtopic=18274

Brewed and pitched last wed with an OG of 1045

I took an sg reading on Sunday of 1022. On Monday I racked half of the 36 litres into another fermenter which had 1.5 kilos of partially thawed rasberries sitting in it. The outside temp was 30 and the temp of the beer prior to racking was around 19. The beer with the rasberries in it has showed no signs of a secondary taking place and on taking an sg the reading today - Wed is 1020. I also took a reading of the beer still in the original fermenter and that also is sitting at 1020 (this is in my ferm fridge sitting at around 18.

So has the yeast decided it is had enough and should I rehydrate and pitch some saf 06 (US56) to finish the job?

From what I have read about the saf wheat yeast here in the forums it seems to be a good working yeast but so far in the week it has been down it has dropped my beer from an OG of 1045 to 1020. I am worried about infection getting into the rasberry wheat as there is no vigerous action going on and as I have introduced a fair amount of air into the fermenter I racked out of 60 litre plastic barrel that too could get an infection.

What to do?

 

[tangent]

did you work out how much the fruit added to the SG?
maybe you've topped it up and the yeast has been working on the fruit and leftover wort.

 

[Mercs Own]

did you work out how much the fruit added to the SG?
maybe you've topped it up and the yeast has been working on the fruit and leftover wort.

No I didnt work that out and in fact dont know how to - there were certainly no breakdowns regarding fermentables on the packet. The fruit was left whole and most has floated to the top of the wort. The beer has taken on a lovely colour and the flavour is good. The fermenter it is in has a very tight seal but has shown no pressure in the airlock.

 

[rwh]

If you're worried about the yeast viability, I'd just pitch another sachet of the SAME yeast as you used originally (saf wheat).

Oh, and you could raise it up a degree or two as well; a wheat is normally fermented a few degrees above a normal ale (to bring out the clove and banana flavours from the yeast).

 

[mfdes]

Actually, US-05 is a good yeast to finish off beers that have stalled without much affecting the flavour.
I have done this twice with wheat beers when they stalled in the 10.20s. By then your yeast-derived flavours are already in the beer and you want something neutral to finish this off.

rwh: warmer temperature encourages banana over cloves. Cooler temperatures encourage cloves over banana. I prefer to ferment mine cool, at 18 degrees and the rule of thumb for German wheat beers is that the fermentation and pitching temperatures should add up to 30 degrees C. This is actually cooler than most ales, not warmer. Be careful when you warm it up, as well as producing more isoamyl acetate (banana), you also increase other esters and fusel alcohols. It's easy to overdo this and end up with a beer with nice banana flavour which is otherwise not that pleasant to drink in large quantities (as a good wheat beer should be).
Most wheat homebrews I've tasted overdo the banana.
MFS.

 

[Mercs Own]

Just might add to this in case you dont read the original thread of brew day that I was aiming for an OG of 1056 but had some kind of misshap and ended up with a 1045. I am now leaning towards a channeling problem during my fly sparge.

So with an efficiency of 60% instead of the usual 75%and a OG of 1045 instead of 1056 could the beer in fact be finished fermenting?

 

[Stuster]

Just might add to this in case you dont read the original thread of brew day that I was aiming for an OG of 1056 but had some kind of misshap and ended up with a 1045. I am now leaning towards a channeling problem during my fly sparge.

So with an efficiency of 60% instead of the usual 75%and a OG of 1045 instead of 1056 could the beer in fact be finished fermenting?

Doubt it. The beer might not know about your original plans for it. :lol: From 1045 down to

I'm not sure why it hasn't dropped any more. A few questions - how sure are you that your thermometer is reading right? (Mash temp was high, and if it was a couple of degrees higher, that's your answer.) And how sure are you that your hydrometer is right? (Have you tested it in plain water?) How many packets of yeast did you use?

 

[Screwtop]

Very strange Merc, I'd be asking the same questions as Stuster, if you added fruit then the SG should have increased due to the sugars in the fruit. Think the temp should be raised after adding fruit, but do a search on that. What amount of yeast did you pitch, I generally under pitch with wheats (.05% for dried) and ferment at 22C. Recently went the other way with the dried weizen yeast and fermented a weizen at 18C it was mashed thin and at 63C it went way down to 1.009.

Screwy

 

[Mercs Own]

Doubt it. The beer might not know about your original plans for it. :lol: From 1045 down to

I'm not sure why it hasn't dropped any more. A few questions - how sure are you that your thermometer is reading right? (Mash temp was high, and if it was a couple of degrees higher, that's your answer.) And how sure are you that your hydrometer is right? (Have you tested it in plain water?) How many packets of yeast did you use?

I cross reference the thermometer with the temp gauges on the mush tun and they are pretty good. Mash temp was higher than I was after but held a steady 69 for the hour. Hydro is calibrated, have tested it and it was spot on. I used two packets of dried yeast rehydrated in warm water at 30 degrees then cooled down and pitched at 23 degrees into 35.5 litres of wort at 22 degrees.

You are quite correct in the beer not knowing about my original plans for it surely has stuffed them up. I followed the usual procedure that I always follow with my brew days - the one exception is that it didnt turn out as per usual.

 

[Stuster]

Sounds like you did everything right to me. Can't see anything there that would end up with that FG. The only thing that makes any sense is the mash temp. It doesn't seem that high, but maybe it's as Wes said and MO is very sensitive to mash temp. Maybe just one to chalk down to experience.

For now, I'd try raising the temp a couple of degrees and see if that helps. Give it a few more days. (I agree with you on wheat yeasts and temperatures, mfdes, but at this stage, there should be very little flavour impact from raising the temperature).

I don't think you need to worry too much about infection. Both have already got some alcohol which will protect them from infections to some extent. There must have been some fermentation of the fruit beer as your gravity was 1022 before the fruit, you'll have added several points with the fruit and it's now at 1020, so you might find it'll keep going a bit. And if there's no progress, you can always try the US05/56.