First AG batch....little problem

[russd32]

I built a mash tun probably a year ago, bought a turkey fryer, aaaaand I didn't get to brew for quite sometime. So I'm a little rusty, I've done probably 6-8 partial mash and extract recipes and haven't ever really had a bad batch.

So for my first AG batch I went to the brewstore that just opened (which is a great place btw, The Hop Shoppe in Bloomington, IL) and the owner set me up with a brown ale recipe and all the ingredients. Brewing seemed to go pretty well, no major hiccups but my fermentation is either stuck or something else is going on. I hit target OG right on the money at 1.052, the recipe says FG should be 1.013. About a week ago I was ready to bottle but I was sitting at 1.025 after 4 weeks in the primary. So I transferred back to the primary and gave the yeast cake a swirl. It seemed to have came back to life with a little krausen and some good airlock activity for another couple days. I just checked again and I'm now at 1.020.

My thought is to let it ride for another week or so to see if the gravity keeps dropping but I'm a little afraid to leave it sitting on the yeast cake much longer. So what do you old pros say? Secondary or leave it alone?

 

[Chamuco]

I'm no old pro but I wouldn't be afraid to leave it on the cake. It's a good sign that rousting the yeast worked. Let it be and check the sg in a week.

 

[Hex23]

It won't hurt to leave it alone. Transferring it again could stir up the yeast, but you can do that without transferring, so why bother further chances of contamination and oxidation. I think the best bet is to stick with the main yeast cake. Autolysis it not very likely. There will be a point at which (without more measures) it's not going to move any more. There are several other thing you could try (warming, repitch, enzymes, etc). But if it is really stuck, consider bottling it if it tastes good.

What was the yeast strain, your fementation temp and your mash temp?

 

[peterj]

How much and what kind of yeast did you pitch? And what temperature have you been fermenting at? I would just let it sit in primary and maybe raise the temperature a little to get the yeast going. Shake it (gently so you don't aerate it) a little every once in while to put some yeast back in suspension. You definitely don't need to worry about it sitting on the yeast cake at week 4. Maybe after week 10 you could think about transferring to a secondary, but I doubt you will leave it that long.

 

[russd32]

I pitched a WLP013 smack pack. I've been fermenting at around 71'ish. It was a little cooler when the carboy was in my downstairs room so I moved it upstairs and I think the cooler temp down there might have been the cause of the stuckage. When I brought it upstairs I did some swirling and put a heat pad next to the carboy. I just did a little more swirling so maybe that'll keep things rolling. I mashed at 160, does that affect fermentation?

 

[Hex23]

I mashed at 160, does that affect fermentation?

Yes, generally 160 is on the high side for a mash and would result in a less fermentable wort. I don't know if it would account for a finish of 1.020. I believe the new Beersmith has an adjustment factor for trying to predict FG based on mash temp and yeast strain's average attenuation.

 

[Hex23]

Yes, generally 160 is on the high side for a mash and would result in a less fermentable wort. I don't know if it would account for a finish of 1.020. I believe the new Beersmith has an adjustment factor for trying to predict FG based on mash temp and yeast strain's average attenuation.

So, for instance, if I put in an 11 lb 2-row grain bill and WLP013 in a 5.5 gallon batch in Beersmith I get the same prediction as you do (1.052/1.013). That's when the recipe is set for a 150F mash which is pretty middle of the road. When I set it to a 160F mash it predicts the FG would be 1.014. However I don't know what science that adjustment is based on. I think there's an adjustable setting somewhere in the program that will change the fermentability based on mash temp. But where it gets that number I don't know. I also understand there are other things like amount of roasted malts (crystal etc) that can diminish fermentability as well.

 

[russd32]

ahhh, I see. The guy at the brew store did tell me to deviate from the recipe slightly so maybe that was his intent since I think that would give a sweeter flavor. The recipe called for 152 degrees and a 60 minute boil and he advised 160 with a 90 minute boil.

 

[russd32]

So, for instance, if I put in an 11 lb 2-row grain bill and WLP013 in a 5.5 gallon batch in Beersmith I get the same prediction as you do (1.052/1.013). That's when the recipe is set for a 150F mash which is pretty middle of the road. When I set it to a 160F mash it predicts the FG would be 1.014. However I don't know what science that adjustment is based on. I think there's an adjustable setting somewhere in the program that will change the fermentability based on mash temp.

Right on, I think I'll keep checking the SG and once it levels out I'll bottle it up

 

[beerguy52]

I think that knowing you mashed at 160 goes a long in explaining your "final" gravity. You have a lot of non-fermentables in your wort. If your gravity reading is stable then bottle/keg it and see how it comes out. I suspect that the mash temp is high for your recipe but if your sanitation is OK then it will be beer. Will not be what you were shooting for but you might be pleased with the result.

 

[russd32]

Thanks for the advice everyone. I don't post much but I've got a lot of great info from this forum. It's been six days and I'm still sitting at 1.020. I think I'll bottle this stuff up the next time I get a chance and see how she turns out.