New to AG, having some issues, need advice.

[Beerphonic]

Hi,
I have been brewing for about 5 years now (mostly partial mash), 4-6 batches a year so not too prolific. Always 5 gallons.
I recently got an AG kit for Xmas from the wifey, and have brewed 4 batches so far. 1 turned out fantastic but the other three have had some issues, one a pretty much a loss.
Basically, I am having trouble getting to my FG. Post boil, my SG has been pretty spot on or maybe 1 or 2 points off. For example I have a Blonde Ale right now (same recipe that turned out great before) that seems to be stuck at a FG of .017 and the recipe says it should be .010. I also had a Brown that was supposed to be .015 and stuck at .028 and that one was perfect on the SG post boil! Yikes!
I am doing a everything the same as when I did Extract other than I am using a yeast starter now. My house does run hot so the Primary is around 70° but it has never been an issue before, at least as far as FG is concerned (I know, off flavors, etc).
I am wondering if maybe something is up with the yeast starter? Somehow not getting enough fermentables from the mash? Bad sparging? Any advice on what you think the culprit could be and some possible suggestions as to some things I could try, I am all ears.

Cheers,
Dean

 

[doug293cz]

Sounds like you might be mashing too hot. This would give you an ok OG, but with more unfermentable sugars than a lower temp mash. With more unfermentables, you will get higher FG's. I would look into your thermometer calibration. If it reads low, then you would be mashing at higher temps than you intended.

Brew on

 

[Homercidal]

The only thing I can think of is that you are mashing too high, resulting in sugars that are not as fermentable as if you mashed low.

So you would have the same OG, but the yeast cannot eat all of those sugars, so they remain behind to keep the FG high.

I'd check your thermometer and see that it's true. There are different ways to calibrate, but the first one that comes to mind is to measure the temp of water mixed with crushed ice and see if it reads at 32F, then get some water boiling hard and check to see if it reads 212 (adjusted for altitude).

This should get you close, but the best way to check is to compare with a known good thermometer at the temps you are measuring.

 

[Homercidal]

Doug, being more concise, beat me to the post!

 

[m00ps]

Agreed I would point to high mash temp issues or maybe the DME that you are using. Extract recipes are konwn to not be able to hit FG due to the set sugar profile from the time of purchase. maybe you are using a different brand/bad batch of DME or a larger portion of it than your other batches?

 

[Beerphonic]

I was thinking too many unfermenatbles could be the issue. I will look into the thermometer calibration. I was thinking of getting a new one anyway so maybe I will just do that. Have a good, not too expensive recommendation?
I know every batch is a bit different but could you recommend a good 'safe' range on the mash temp? I know there was one batch were I thought I actually might be low.
Also, when moving into sparging from mashing, what temp do you heat your sparge water to and do you want the temp to be when that water is mixed with the mash concoction?

 

[JordanKnudson]

I was thinking too many unfermenatbles could be the issue. I will look into the thermometer calibration. I was thinking of getting a new one anyway so maybe I will just do that. Have a good, not too expensive recommendation?
I know every batch is a bit different but could you recommend a good 'safe' range on the mash temp? I know there was one batch were I thought I actually might be low.
Also, when moving into sparging from mashing, what temp do you heat your sparge water to and do you want the temp to be when that water is mixed with the mash concoction?

I use a cheapo Big Daddy thermometer from my lhbs. It works fine, but needs to be recalibrated from time to time (very easy to do). I recently checked it after not bothering for a long time and it was reading 10 degrees too high! Needless to say, my mash temps were low and my beers were drying out something fierce. Still, a simple recalibration and voila, it works like a charm again.

A very safe range for your mash temps would be between, say, 148F - 153F. You can go outside of that by several degrees and still get conversion (the real range is something like 142-160, maybe even a little wider), but then you will be really favoring one amylase enzyme over the other and it will make a difference in the final product and in your required mash times.

 

[m00ps]

I was thinking too many unfermenatbles could be the issue. I will look into the thermometer calibration. I was thinking of getting a new one anyway so maybe I will just do that. Have a good, not too expensive recommendation?
I know every batch is a bit different but could you recommend a good 'safe' range on the mash temp? I know there was one batch were I thought I actually might be low.
Also, when moving into sparging from mashing, what temp do you heat your sparge water to and do you want the temp to be when that water is mixed with the mash concoction?

I do my mashes between 148-155 usually. 148 would be for a Belgian tripel or saison, though ive done 146 before. 155 is for stouts and ESBs. I usually do a 10min mashout at 168 too. Ive read it destroys the enzymes to lock in the sugar profile of the wort before proceeding

For sparge water, you should use a online tool to determine it based on your target temp and water volumes

 

[Homercidal]

I have been using a cheap CDN thermometer from Walmart. Digital, fairly fast display.

If you get anything cheap just be sure to test it.

Otherwise the only thing I can recommend is the Thermapen, which has great reviews, but costs like $70 or so...

 

[MindenMan]

I use an $8.00 floating dairy thermometer. Calibration is good too.

 

[Qhrumphf]

Because I like to burst bubbles....

You need to be careful with thermometers. Like @Homercidal said, the best way to know a thermometer is accurate is to check it at mash range. The problem with calibrating at boiling and freezing is that many thermometers (particularly cheap ones) have a wide temperature tolerance of a few degrees, and can be perfectly precise reading, but not an accurate one, in mash ranges, even when accurate at freezing and boiling. And those few degrees, when dealing with mash temps, can make a big difference. I had this happen with a cheap "lab" thermometer- it was accurate at boiling, accurate at freezing, but when it read 152 it was actually 147. That was enough that I had major overattenuation problems. Once I switched to a better thermometer with a narrower tolerance, problem went away. If you have a thermometer that's reading low, and you think you're at 152, and you're actually at 156, that could be a large measure of your problem right there.

So I'd recommend forking out the additional money and getting a good thermometer, one with a tolerance of no more than +/- 1 degree. There are some accurate cheaper ones, but I've had nothing but good luck with the Thermapen, which unfortunately is about $100, but it's one of the best brewing investments I've made.

 

[JordanKnudson]

Because I like to burst bubbles....

You need to be careful with thermometers. Like @Homercidal said, the best way to know a thermometer is accurate is to check it at mash range. The problem with calibrating at boiling and freezing is that many thermometers (particularly cheap ones) have a wide temperature tolerance of a few degrees, and can be perfectly precise reading, but not an accurate one, in mash ranges, even when accurate at freezing and boiling. And those few degrees, when dealing with mash temps, can make a big difference. I had this happen with a cheap "lab" thermometer- it was accurate at boiling, accurate at freezing, but when it read 152 it was actually 147. That was enough that I had major overattenuation problems. Once I switched to a better thermometer with a narrower tolerance, problem went away. If you have a thermometer that's reading low, and you think you're at 152, and you're actually at 156, that could be a large measure of your problem right there.

So I'd recommend forking out the additional money and getting a good thermometer, one with a tolerance of no more than +/- 1 degree. There are some accurate cheaper ones, but I've had nothing but good luck with the Thermapen, which unfortunately is about $100, but it's one of the best brewing investments I've made.

No one's going to disagree that the Thermapen is awesome. Just wish they weren't so dang expensive...

 

[Qhrumphf]

Also, I mash anywhere from 147 when I want a really super dry beer, to 158 if I want something good and filling and dextrinous. I have gone higher before, did a 160F mash once without issue. But there's usually not a reason to go that high.

As far as sparging, the way I see it what matters is the temp of the grain bed once the sparge water is mixed in. A grain bed of about 167-168 is what I'd be aiming for- enough to stop enzymatic conversion and make sure all the sugar is good and soluble, but low enough to make tannins not a problem unless you really oversparge. As a consequence, it depends on how you're sparging. If you're fly sparging, I wouldn't go higher than 170-175. I get plenty good efficiency batch sparging, and I do it English style (drain mash tun, add sparge water, rest, drain again, add more sparge water, rest, drain again), so I usually have my sparge water closer to 185. Of course, it also depends if you're doing a mashout or not. If you're mashing out, you may need to go cooler, if not you may need to go warmer. Point is, if your grain bed is over 170, you're too hot.

 

[Beerphonic]

Hmm. The only thing I can think of is that my thermometer is off. I will try and check it and see. I know I have not had a mash, according to my thermometer, that has been too high. I am pretty careful and follow the recipes as best I can. I think my mashes have been between 150° and 155°. I will keep it on the lower side in the future to see if that helps. Maybe a little longer on the mash might help as well.
I have the Miljoco thermometer from the LBS. Doing some Googling and discovered its pretty bad. Guess I know what the next beer supply purchase is...

 

[Beerphonic]

Well, well, well... I just did a little ice water calibration on the thermometer. It was a good 8° low!!!
No wonder my beers were all messed up. I have been reading say, 152° on the thermometer and its really 160°! :smack:
Lesson learned I guess. I will testing that out every brew day from now on. Still might invest in something a bit better.
Thank you everyone for your help!!!

cheers,
Dean