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View Full Version : Stir-plate Braggot fermentation questions



zambo
10-31-2012, 04:00 PM
Hi, I just started a batch of "Hefty Braggot" from Ken Schramm's book, with a few modifications. Here are the ingredients and techniques I've used so far.

6 lbs. Amber malt dme
4 oz. cascade hops 60 min.
2 oz. cascade hops 30 min.
2 oz. cascade hops 2 min.
9 lbs. raw buckwheat/wildflower honey
10 gr Lalvin D-47 yeast
12.5 gr go-fern protect
15 gr fermaid-k
2 gr DAP
OG 1.110
room temp~52-56 F

Mix malt with 5 gal. filtered tap water(brita).
Boil with hops for 60.
Chill with wort chiller down to ~ 80 F
Strain into pail with honey, mix well
Pour into 6.5 gal. glass carboy
Aerate with .5 micron diffusion stone hooked up to an aquarium pump
Drop sanitized 2" stir bar into carboy and place carboy on stir plate, start stirring.
Rehydrate go-firm in 85 ml h2o at ~111 F, add yeast at 104 F. Rest for ~ 30 min.
Pitch yeast/go-ferm into must, and cover opening loosely with cloth.
After 12 hrs. add 4 gr fermaid-k + 2gr DAP, keeping air pump and stir plate going. Lots of krausen coming out.
SG at 16.5 hrs(after initial pitch) 1.100
SG at 29.5 hrs 1.074, Add 6 gr fermaid-k (1/3 sugar break), remove aerator, and attach air lock.
46 hrs. SG 1.040, aerate with stone for 3 min. created lots of krausen.
65.5 hrs SG 1.034, bubbles from air lock every 10 sec, add 5 gr fermaid-k, stir with lees stirrer attached to drill to de-gas. Aerate with stone for 20 min. Air lock and continue on stir plate.

This is were I am at so far.

I just have a few questions regarding the process.

1. Is there any danger in aerating continuously up to a certain point?

2. How long should I expect the gravity to come down to ~ 1.018, from this point?

3. Any thoughts on the amounts and scheduling of my nutrient additions, and choice of yeast?

4. Is the gentle stirring provided by the stir bar enough to keep CO2 levels down? I am using a black maxx stir plate, but it cannot be run over 1/4 speed without throwing the stir bar, although it definitely keeps the yeast in suspension, even at slow speeds. When I stirred the must with the lees stirrer attached to a drill, it did release a 1-2" layer of gas(foam).

So far, the smell and taste of this brew is very pleasant.

I will try to update as the fermentation progresses.

Thanks for your input.

Zambo

Chevette Girl
10-31-2012, 08:50 PM
I haven't made a braggot yet so I'll only answer the stuff I have a valid answer to :p

There shouldn't be any danger in continuous aerating up to 1/3 sugar break. After about the halfway point though, the yeast don't really need the oxygen. They also can't really use much of the nutrients past the 1/3 break, so all you're really doing at this point by feeding and aerating is risking oxidation and feeding other organisms. This is why it's usually recommended to go by SG's and not by time, you never know how fast your yeast are going to do their thing.

D47 is a great yeast if you can keep the temps down, which it appears you can :)

Continuous slow stirring is probably great for decreasing CO2. Any amount of stir-plate action is better than none at all. More agitation will release more gas more quickly, but I'm sure your stirring is still doing something.

zambo
11-01-2012, 11:44 AM
Fermentation has really slowed down now. SG went from 1.034 to 1.032 in about 20 hrs. Only getting a bubble out of the air lock every 30 sec. or so. Room temp this AM about 52 F.

The recipe calls for a finishing gravity of 1.018, but I don't see that happening, unless I can get the ferment going a little stronger.

Is it normal for it to slow down a lot at this point, and will it eventually go down that low(1.018), and if so, how long would it take?

Is it possible that my fermentation temp is too low?(low 50's).

Is it also possible that I did not use enough DAP? I thought that with all that malt in the must, that nutrients would not be an issue. Also there seems to be some general concern out there about using too much DAP, and when to add it.

Should I consider re-pitching with a stronger yeast(I have some K1V-1116), to get it going again? And/or raising the temp. of the room? If I don't, would there be enough life in the D47 to bottle condition?

I'm still using the stir plate, keeping the yeast in suspension.

Also, should I be racking into secondary carboy at this point?

Thanks

Chevette Girl
11-01-2012, 12:20 PM
It is quite possible that your fermentation temp is too low. You'll have to check up on D47's tolerance though, you do NOT want to be near the high end of it, but getting up into its low end would be a good idea. Going from memory I think it's fine in the 60's and maybe up to very low 70's but don't trust me on that, look it up either on the yeast table to the left or on Lalvin's webpage.

I would think you're probably OK on nutrients, having used malt. With DAP, I don't use more than the package's recommendation, which in my case is 1 tsp per gallon (I think that works out to around 5 grams) and I want to get it all into the must before the 1/3 sugar break. If I add yeast energizer, I usually take that amount away from the DAP I'm adding, I generally end up with 1/2 tsp each per gallon, but some yeasts like RC-212 are nutrient-hogs so I'll go add half-again what I'd used in total.

Your yeast is probably fine, given your initial SG, I think D47 should be able to take that dry aside from the unfermentables from the malt and still be able to bottle-carb later.

It's probably just slow because of the temperature. If you warm it up some, you'll probably see an increase in the rate your SG is dropping, but even without, you're still getting a visible drop within a 24-hour period so it's still doing something. I'd leave it on the stir plate and not rack to secondary until the SG has been parked at the same reading for a couple of days, then let it settle out and rack it. If yours goes like other stir-plate batches I've read about, it will probably drop pretty clear very quickly but there should still be enough yeast there to do the job by the time you're ready to prime and bottle it.

zambo
11-01-2012, 01:16 PM
Thanks, I know I'm at the low end of the range for D47(50-86), so I will bump it up to the low 60's from the low 50's and see what happens.

It was such a strong first 2/3's, that I thought it must be something other than temperature, but lets hope that temp. is the issue. I don't want to raise it up too much, due to issues I've heard others have had with off flavors from D47.

Thanks again for your input

Chevette Girl
11-01-2012, 01:18 PM
It's not uncommon for fermentations to slow down near the end, but as long as it's still going somewhere at a perceptible rate, there's hope :)

zambo
11-10-2012, 12:20 PM
As of Nov. 9
SG 1.030
PH 3.96
Temp~65 F

Hi, it seems that my yeast has decided to crap out earlier than I had hoped. The braggot had a very strong, healthy ferment, and already tastes very good, but has ended up with more residual sugar than expected.
Should I re-pitch with a stronger yeast, or just prime and bottle?

One of my worries is that the yeast won't be able to consume the priming sugars(honey), considering it is not consuming the residual sugars already available to it, and that I will end up with an even sweeter braggot with little carbonation. Or should I consider just bottling it the way it is, and hope that the yeast continues to work away(albeit slowly) at fermenting out some of the remaining sugar, in the bottle?

Thanks

thargrav
11-10-2012, 01:04 PM
4. Is the gentle stirring provided by the stir bar enough to keep CO2 levels down? I am using a black maxx stir plate, but it cannot be run over 1/4 speed without throwing the stir bar, although it definitely keeps the yeast in suspension, even at slow speeds. When I stirred the must with the lees stirrer attached to a drill, it did release a 1-2" layer of gas(foam).

Zambo

This is Tom, I designed and we manufacture the Black MAXX Stir plate. It's typical for that model to not spin past 1/4 speed for 5 & 6 gallons & the reason is the resistance against this much volume is so great that the stir bar shears away from the drive magnets. I am incorporating a running change that will help solve the problem - as of this month we will start building with 33% stronger drive magnets.

Thanks, Tom Hargrave
www.stir-plate.com

Chevette Girl
11-11-2012, 02:33 PM
Wow, isn't that cool to have your equipment's designer find and comment on your post!! ;D Although looking at the website, it doesn't actually mention the Black MAXX anywhere I saw. <shrug>

If this yeast is done, it's done, and if there's residual sugar, priminig it won't do anything, and if it's still slowly going to chug away, it's not safe to bottle that with residual sugar still present because there's no telling exactly how much of your 1.030 is still fermentable and there's no telling where it might stop and if that will be before or after it's blown some bottles apart.

If you're determined to see this batch carbonated, you may have to go with another yeast, but I'd do an acclimated starter and see if it'll finish what your D47 has left behind, BEFORE you prime and bottle... I'd suggest EC-1118 because it's one of the better ones for restarting stuck ferments and it's got a high tolerance, although K1V's tolerance is near there anyway...

Slownewone
11-14-2012, 01:39 PM
Hey Zambo-

I made this recipe ~6 months ago and had similar issues with stalled fermentation. My ferment was very healthy and then stopped at 1.040. This was despite using 10 grams D47 re-hydrated in GoFerm plus addition of 7.5 grams Fermaid K at lag and aeration on day 2, for a 2.5 gallon batch. I fermented @ 62 F.

At any rate, I searched around the net to see what experiences others had with this recipe and found a good volume of evidence that it is common for the extract batches to stop early. There's at least one other thread on Gotmead around this issue and a group of folks who group brewed this recipe. As such, my hypothesis is that unfermentables in the DME caused the early stop. Perhaps this is specific to amber DME, I'm really not sure. I can say that I am very surprised that there would be so many unfermentables, given the contribution to the S.G. from DME so maybe there is something else at play.

What I can say is that I tried a number of techniques to get my Hefty going again (including raising temp, swirling, addition of EC-1118) and then decided just to leave it be. I bulk aged for 3 months, then bottled with priming sugar. The braggot carbed up just fine to ~3.2 volumes in about one month at room temp and here's the kicker....it tastes FANTASTIC. While it is perhaps a bit sweet, the bitterness from the hops balances the sweetness nicely and also helps to counter the high alcohol content. I have certainly had a number of big imperial stouts and barleywines that had a similar level of sweetness.

So, if I were you, I would bulk age this to clear and ensure it is truly done, then add bottling yeast and priming sugar and bottle. Just my two cents but I think that there is enough evidence to support that you don't have a stall. My guess is that maybe the extract version of the recipe was not tested prior to print but that's just a guess.

Either way, it does turn out tasty and if you want a drier braggot, try the all-grain in the future or maybe go mini-mash.

Midnight Sun
11-14-2012, 04:24 PM
Zambo, I made a test batch of this about a year ago and concur with much of what Slownewone says. We differ in that is way too sweet IMO, but when chilled it is better.

For some reason, the extract version simply stalls around 1.030 for many people. I have done extract barley wines using amber LME and the same thing happened: stall around 1.030. There is little doubt in my mind that amber LME must have a higher proportion of unfermentables compared to all grain, since fermentation restarts when you add table sugar or honey. Light LME may be a different story, not tried it yet.

At some point I will make this again, but it will be in small batches using the brew-in-a-bag method or mini-mash.

If you want the current batch drier, you could also blend with a dry trad. You're probably better off just bottling, though.

zambo
11-14-2012, 07:42 PM
Thanks for your input guys, I was starting to wonder about that being the problem myself.
Thankfully, I increased the hops in the recipe, and it has come out well balanced, maybe a touch sweet, but overall very tasty.
I think I will just let it clear bit more, and then bottle.
I am hoping that the D47 already in the Braggot will be able to consume whatever priming sugar I use, probably honey. Slownewone mentioned using a bottling yeast. Is that necessary? I've never done that with beer before.
Also do you recommend racking it into a secondary carboy, or just let it settle out in the primary carboy?

Thanks

Zambo

Slownewone
11-16-2012, 12:23 AM
No problem at all.

On your priming yeast question, given that you will be bottling in a relatively short period of time, there shouldn't be any need to add yeast. I aged my hefty in bulk for somewhere around 4 months so made the decision to add it. I probably could have gotten away without adding it but these days, I tend to play it safe. Having had carbonation issues with both bulk aged cysers and beers, I'll happily spend the additional $2 on priming yeast for security. Up to you on racking or just leaving it in primary to settle. Since I aged for a decent period of time, I decided to rack (also b/c I didn't want to mess with stirring the lees). If you plan to bottle this in the next 6 weeks or so, I don't believe it should be an issue, particularly given that meads with D47 can be lees aged.

Like you, I bumped up the hops on the standard recipe (I think I doubled up and used Columbus and Chinook instead of Cascade, though my IBUs were relatively equivalent). I really was pleased with this one...surprising, because normally I'm not a fan of sweeter beers, meads, or wines. This one was certainly not cloying (definitely not at the level of Samichlaus or JW Lees) and I believe it will age nicely. Also, given the concerns I had based on the high F.G., my perspective may also play in. At any rate, glad to help out and good luck.