Low gravity

[smertin]

Just done my first run with my new robobrew. Making a stout and the est pre boil gravity is 1.050, measured mine and it only came in at 1.030. Im hoping it was a dud reading and when i put it into the fermenter tomorrow it has a higher OG. If it is a bit low tomorrow though should i maybe add a bit of dextrose in to raise it or stick to the recipe?

 

[Ben Davies]

Just done my first run with my new robobrew. Making a stout and the est pre boil gravity is 1.050, measured mine and it only came in at 1.030. Im hoping it was a dud reading and when i put it into the fermenter tomorrow it has a higher OG. If it is a bit low tomorrow though should i maybe add a bit of dextrose in to raise it or stick to the recipe?

Dextrose will thin the body if you want to raise gravity use DME.

You might wanna look into why you got so low conversion as well...

 

[JDW81]

Did you correct for temperature? If you measure wort at mash temps then your gravity will read lower than at 20 degrees.

 

[smertin]

I didnt account for that actually! That makes me so much happier was thinking maybe it was because i made the grains too fine and they blocked up the pump. But then again its not a necessity to recirculate is it! Hopefully all will look good tomorrow when i put it in the fermenter!

 

[MHB]

Yes it is necessary to recirculate, well no it isn't but it is necessary that the water be able to get at the malt otherwise they might as well be kept in separate buckets.
You can do an isothermal mash just by mixing the malt and water at the right temperature, but then why not just get a BIAB setup rather than spending money on a pumped recirculating system.
Grind too fine and the water wont get in - you can in effect create one giant dough ball - if you don't know what you are doing why not order a grain bill from someone who does, have a look at how the malt is cracked and adjust your mill to get a similar looking grist.
The error from measuring the sample too hot wont be too far off 20 points (at 70oC your 1.030 is really 1.048) well worth testing at the right temperature or doing the correction Brewers Friend attached to this forum has a handy calculator.
Mark
PS - A decent introduction to gravity
M

 

[smertin]

I was testing out the mrs thermomix for the grain hoping it did the trick but doesnt look like its any good for the job. As you say next time i will get someone who know what theyre doing to grind it for me. Was testing out grinding myself as when i move to my new house (couple of months away) i wouldnt mind stocking up on some bulk grains, may have to invest in a mill when i get there. As you mentioned it did come out at roughly 1.050 after the temperature adjustment but strangly when ive put it in the fermenter this morning now it is at 22 degrees and only measuring at 1.036 :S

 

[stuartf]

Seems like an obvious point but always make sure you have given the wort a good stir before taking your gravity sample too. If it's not well mixed after sparging you will be measuring a more diluted sample than the actual wort. I made this mistake on my first AG brew and thought I had mid strength lager only to find a few bottles of the stuff was getting me pissed quite easily [emoji38]

 

[smertin]

Seems like an obvious point but always make sure you have given the wort a good stir before taking your gravity sample too. If it's not well mixed after sparging you will be measuring a more diluted sample than the actual wort. I made this mistake on my first AG brew and thought I had mid strength lager only to find a few bottles of the stuff was getting me pissed quite easily [emoji38]

I cant remember for the life of me if i did give it a stir but i tried to skimp out and got a plastic paddle, snapped on the second stir of the grain. Got myself a proper ss paddle now so will definately make sure i stir on the next batch!

 

[Schikitar]

I'm very much a beginner myself BUT perhaps go watch some more Robobrew brewday videos on YouTube (by reputable home brewers) to see how they go about things. It's better to research and understand as much as possible about your system and the associated techniques than it is to try and reinvent the wheel and simply cross your fingers.. best way to learn is through mistakes but most mistakes can be avoided in the first place!

This guy has heaps (he uses a Grainfather but the ideas are the same), just set the video playback speed to 1.5 because he talks slow AF - https://www.youtube.com/channel/UCb3HYxTpCaVDeulH1mZGW1Q/videos

 

[smertin]

Perfect, thanks for that! Ill have a look at some when i get some spare time!

I'm very much a beginner myself BUT perhaps go watch some more Robobrew brewday videos on YouTube (by reputable home brewers) to see how they go about things. It's better to research and understand as much as possible about your system and the associated techniques than it is to try and reinvent the wheel and simply cross your fingers.. best way to learn is through mistakes but most mistakes can be avoided in the first place!

This guy has heaps (he uses a Grainfather but the ideas are the same), just set the video playback speed to 1.5 because he talks slow AF - https://www.youtube.com/channel/UCb3HYxTpCaVDeulH1mZGW1Q/videos

 

[citraman1]

Hi Smertin, let me know how your fermentation goes. Ive completed about 6 brews in the 2nd gen robo and I havent had one batch yet that has made it down to its correct FG. I have been pitching 2 packs reydrated yeast and my mash temps and sparge water temps are as close to correct as I can get so Im not sure why my wort fermentability has been so low

 

[smertin]

Hi Smertin, let me know how your fermentation goes. Ive completed about 6 brews in the 2nd gen robo and I havent had one batch yet that has made it down to its correct FG. I have been pitching 2 packs reydrated yeast and my mash temps and sparge water temps are as close to correct as I can get so Im not sure why my wort fermentability has been so low

Very strange. Do you have the correct profile for your machine? This one didnt hit the est OG due it being a stuck sparge i think (didnt let it rest for 10 mins before recirculating) and it was just all running down the centre pipe. Just did a small batch this weekend and gave it a good stir at the start. Closed the valve a little so the recirc was a little slower and as soon as i saw it was slowing doen i gave the grain a good stir again to let it flow through, think i did 3 stirs over 30 mins and then got a good recirculation for the remainder of the mash. Est OG was 1.044 and i got 1.044!

 

[citraman1]

What do you mean by profile? I use a complete water profile recipe specific and I have always hit my OG or a little over, I have a temp controlled freezer for fermentation and over pitch yeast so Im just not sure why Im not getting my FG. Watched heaps of robo vids and just cant figure out what the problem is

 

[smertin]

Ah sorry i was thinking you were saying you were struggling to hit your OG. I cant say i have any solutions for you with the FG as i dont temp controller my fermentation as yet, hoping to get it sorted in the near future though! All i do is pitch the amount of yeast it tells me on beersmith and leave it in the cupboard for a couple of weeks, havent had any problems doing that so far though

 

[Ben Davies]

Try mashing lower like around 62c for 40mins - 1 hr this should give you a more fermentable wort. Also adjust ph and make sure youve got atleast 80ppm calcium in your brew water to keep them yeasties happy.

Another thing of course is type of yeast used knowing its average attenuation to give you an idea of when where fermentation should finnish.

 

[citraman1]

Cheers Ben Ill try lower mash temps, my ph levels are good and my water profiles hit the 80ppm so ill try that first

 

[Mister clark]

Just throwing this out there as it may help others.

I had issues with my conversion using a MillMaster mill, tried loads of different gap settings.

The issue was actually th drill I was using, I went and bought a low speed high torque Ozito and my converion has gone from somewhere in the high 60s to mid 80s - nothing else was changed.

My latest Hefe has come in at a powerful 5.9% haha!