oxygenation/attenuation question!

[perry]

I want to run this by all of you out there…I drain my boiler right out of the bottom and I’ve always oxygenated my wort prior to pitching by simply cascading it down the side of the carboy. If I’m careful, I get a sheen of wort over about a third of the glass and a fan, or ribbon, in the middle …( those who do this, I hope you know what I mean).

I realize that one of the limitations of this is that the wort coming out of the boiler toward the end has less chance to take on oxygen due to… well, less air time.

Problem is, I’ve been getting terminal gravities of 16 to 20 with recipes that should produce gravities of 9 to 13, resulting in an annoying (to me) sweetness. I mash at 151-148, and my fermentation temps are right on (low side of the range).

Do you all think maybe this method is not effective enough to provide the yeast with all the oxygen they need? Maybe they are pooping out before their job is done?

Thanks for any feedback. -p

 

[RichBrewer]

What kind of yeast are you using? It might be a fairly low attenuating strain which would cause your high FG. Also, what are your fermentation temps?

As far as oxygenation goes, I shake the dickens out of the carboy after it is filled. I think I'm going to get an oxygenation system though. I've heard they work better and much faster with a lot less work.

 

[perry]

Thanks, Rich. The higher gravities seem to happen no matter what yeast I'm using. Mostly I brew ales, using irish ale or american ale 2 yeasts from Williams.

Fermentation temp is 60- 64 deg.

As far as the oxygenation systems go, I'm considering this too. Has their been a discussion here about them?


-p

 

[david_42]

There are couple threads on oxygenation and I suspect that's your problem. Your method probably only introduces 2-3 ppm O2, whereas shaking will get it up to 6-8 ppm and O2 injection 30-33 ppm.

I use an air pump with a stone and do several injections in the first 5-6 hours.

 

[RichBrewer]

Thanks, Rich. The higher gravities seem to happen no matter what yeast I'm using. Mostly I brew ales, using irish ale or american ale 2 yeasts from Williams.

Fermentation temp is 60- 64 deg.

As far as the oxygenation systems go, I'm considering this too. Has their been a discussion here about them?


-p

Here's one I started.

https://www.homebrewtalk.com/showthread.php?t=18173

 

[mysterio]

Aeration sounds like the problem, this is crucial when you're using a liquid yeast.

When you're making a starter, aeration is also critical. I give my starter several 10 minute blasts with an aeration stone & aquarium pump.

 

[Evan!]

Problem is, I’ve been getting terminal gravities of 16 to 20 with recipes that should produce gravities of 9 to 13, resulting in an annoying (to me) sweetness. I mash at 151-148, and my fermentation temps are right on (low side of the range).

Do you all think maybe this method is not effective enough to provide the yeast with all the oxygen they need? Maybe they are pooping out before their job is done?

I'll chime in, because I had precisely this problem. For the longest time, I honestly couldn't get my FG below 1020. But I was talking with a local brewmaster, and he said that I really should be force-aerating my wort. So I dropped a measly $30 on the aeration kit at Austin Homebrew (comes with a pump, the tubing, an inline HEPA filter, and the aeration stone). What I do is, right after I strain my cooled wort into the carboy, I pitch my yeast/starter, then I put the aerator into it for about an hour. Easy as pie. Ever since I took on this tactic, my attenuation has increased by about 10% on average. Of course, you could go the oxygenation kit route, but that also requires getting O2 tanks...which is just another hassle I don't need, even though it is more effective/efficient.

 

[Steve973]

Yup, I'd recommend investing the $30 for the oxygen kit. You'll notice that your fermentation kicks off much faster! And think about it... You can oxygenate your starters, too. Since the most crucial time is the ramp-up time for the yeast, it's always great to give them as much of a kick start as possible.

By the way, it's easy/cheap to find tanks of bernzomatic oxygen.

 

[bandt9299]

I got the oxygen kit for Christmas and have never had a stuck ferment before (2 years and 54 batches) , now I've used it on the last 2 batches and both have stuck in the mid 20's!! The one I have in the primary now is a Guinness clone and was only 1.042 to start and after a week is still 1.026 with no activity, just the opposite for me, really really weird!!!

Now i'm trying to decide if I should pitch some more yeast, only I have no more Irish ale yeast, I would have to pitch nottingham dry?

 

[perry]

Thanks for the discussion everyone. Anyone recommend a particular brand of aeration system? Is it better to go with pure O2? Which ones are easiest to clean? Which ones work fastest?

I'm excited by the potential here....

thanks, -P

 

[Bobby_M]

I plan to put a couple methods of oxygenating to the test next weekend so stay tuned. I think the cheapest way to get into pure O2 is to buy the standalone regulator from Williams Brewing for $16 and get your own tubing and aquarium diffusing stone and Benzomatic O2 bottle at Depot. Should be under $25 total. You don't need the hepa filter or stainless airstone if you want to go cheap. Also, keep an eye out for used medical O2 bottles on Craigslist.

 

[perry]

Bobby, I'll look forward to hearing of your results.... I called my local welding supply and they just laughed when I said "disposable," so I may be eventually throwing down for a refillable O2 tank and regulator. But I want to fingd out if this is the solution to my "sweetness" problem first.

-p

 

[Steve973]

Yes, it'll be cool to see the results of this experiment. I know that I have my *impressions* about what oxygenation gives us, but it'll be interesting to hear your results.

Perry, it all depends on where your sweetness comes from. If it's from dextrins, then there's not much you'll be able to do about that, other than altering your mash temperature(s).

 

[perry]

Steve, I'm pretty sure it's not from dextrins.... I've been playing around with reducing the number of unfermentables over the last several batches (did one five-gallon batch with less than 1/2 lb of crystal and carapils combined), and my mash temps are quite low.... That's why I'm intrigued by this whole oxygenation/attenuation thing... still looking for a source of those O2 bottles though.

-p

 

[Steve973]

Ok, well if you're mashing at, for example 146F for an hour and a half, and if your mash water is at a pH of 5.2, then the next step would probably include a decent starter and oxygenated wort.

 

[perry]

So, I had this grand experiment planned but bungled it (sort of). However, I must say that the batches of IPA from this weekend started faster and more vigorously than I've seen before...

Ill be using bottled O2 and an aeration stone in every batch from now on.

I suppose I could provide the whole saga here if anyone is curious...

-P

 

[boo boo]

I racked a hobgoblin wort onto a yeastcake (hobgoblin) and oxygenated with my new o2 system and got the most voilent blowoff I have ever experienced and it all started within a hour of racking.
I'm sold on oxygenating vs aerating.

 

[AleHole]

still looking for a source of those O2 bottles though.

-p

You can find those disposable Bernzomatic O2 bottles at Lowes in the tooling section where the propane torches are. They are red bottles and have left hand threads so you will need a special regulator for those. You can get those at most homebrew stores online. Hope this helps. Try http://www.williamsbrewing.com/WORT_AERATION_C106.cfm

I have the setup with the regulator and the wand. Works like a champ.

 

[perry]

Thanks alehole, I did find them at the hardware store here...although out here the bottles are green. When I was uncertain before, I had called around and no-one knew what I was talking about; I just had to go look myself. I bought the kit from Williams as well... those guys are great- I order Monday, it's here on Tues.

You're right. I works better than I could have imagined. Thanks for the reply.

-p

ps. fermentation in that batch I was talking about has slowed, but I'm too lazy and too tired to check the gravity... I usually just go by the airlock anyway...