Not as much wort as I expected. Low gravity. What to do?

[BobShandy]

I bought a second Kettle (tank) from ebay. It is handy because it has thin sides and heats faster than my original tank. My original is 30 litres and this was sold as 30 litres. Mine could be bigger than I thought, the new one could be smaller. Or perhaps they are the same and that isn't the issue.

I have a recipe I enjoyed from my first brew; 1 KG oats, 4KG malted barley. Last time I added gluco amylase to make a really dry beer. This time I left it out, and added 50g of Kent Hop Goldings in the last 15 minutes of the boil. I use US-05 yeast.

This was my process

1. Leave the 22 or so litres of water in the kettle tank overnight to allow any chlorine to evaporate
2. Sanatise everything necessary with no rinse sanitiser
3. Put the oats and malted barley in a bag in the kettle and start to heat the tank
4. Keep the heat at 64C for one hour. It crept up to as much as 67, and down to 63. Stir every so often. No clumps found.
5. I put a grill over the kellte tank, with the oats-barley filled bag, and sparge boiled water through and squeeze some of the "juice" out.
6. I put a lid on the tank to get it to boil, ten minutes of boiling, then lid off and 96c (max I can get) for about an hour.
7. Last 15 minutes I added kent goldings hops (50mg) in a bag
8. Cool the mix down to 25c with my wart chiller
9. Use a sterile electric whisk to introduce air into the mix, with some stirring with a sterile metal paddle.
10. Measure with a hydrometer - reading 1.034 - I think this is a low result? I read it accurately and checked several times.
11. Open the spout in the kettle and eject the liquid into the sterile fermentation tank
12. Pitch the hydrated yeast. I dropped some of my US-05. So I ended up using 1 + 2/3 10g packets. Ideally I would have used one packet.

In the new kettle there is a wire mesh leading into the tap. It filters out a lot of crap. I ended up leaving about 300ml-600ml of sludge in the tank. Was that a mistake?

I think I got only 16 litres out of the process.

I may have screwed up with the sparging. The previous time I did it for a far longer time and far more carefully. Perhaps I extracted a lot more of the sugars?

The previous time I believe I did everything at a higher temperature.

Where do I go from here? I was thinking of boiling 4 litres of water, letting it cool, adding some appropriate quantity of maple syrup and putting this in the mix, and then seeing what the new gravity is.

 

[BobShandy]

I ended up boiling water and adding brown sugar, caster sugar, honey, maple syrup, which was all I had around, and bumping the gravity to about 1.050. But I had over filled the tank by misjudging how much more water I needed. I probably have 4 inches space plus the convex lid at the top of the tank.

I checked the gravity about a week ago and it indicated 4.20% Abv. I stupidly thought I had to add some air, so I whisked in some air using steralized equipment. Afterwards I saw this was a mistake as it could switch the yeast away from prouducing CO2 and I might end up with buttery "off" flavours.

Today I checked the gravity and it indicated the beer is now 5.91%. It tastes lovely. I think I will leave it in until the beer has had a complete month.

 

[BobShandy]

If I want to reuse the yeast for my next batch, do I leave the tank out in cold (but not freezing) temperatures to cause the yeast to fall to the bottom of the tank, so that I can scoop it out once I've siphoned off and bottled the beer?

 

[Agentgonzo]

If I want to reuse the yeast for my next batch, do I leave the tank out in cold (but not freezing) temperatures to cause the yeast to fall to the bottom of the tank, so that I can scoop it out once I've siphoned off and bottled the beer?

You shouldn't need to leave it in the cold. There will be loads of yeast settled at the bottom at room temperature

 

[BobShandy]

How do I have 90% attenuation at this stage? Does it come from the oxygenation which I added a week ago (frisking in air with a whisk)?

I read that the yeast cell membrane needs oxygen for cell health. I wonder if my second oxygenation gave the yeast a boost.

Or it could be that I ended up using 1 + 2/3 of US-05 yeast? Lots of yeast means high attenuation?

 

[JustJordds]

How do I have 90% attenuation at this stage? Does it come from the oxygenation which I added a week ago (frisking in air with a whisk)?

I read that the yeast cell membrane needs oxygen for cell health. I wonder if my second oxygenation gave the yeast a boost.

Or it could be that I ended up using 1 + 2/3 of US-05 yeast? Lots of yeast means high attenuation?

Seems like it could be a mix of the extra stuff you threw in with high sugars for the yeast to eat at and then the two packets of yeast used.

My advice (which is what helped me massively) is to use software to track the brew (it’ll give you target OGs, FGs, ABV and sometimes how much water to use for your mash and your sparge) so you’ll be able to see where you may have gone slightly off-piste!

I would usually wait until the kettle is at 66 degrees before even dropping my grain bill in so. It sure if that may have had an affect?

 

[BobShandy]

Seems like it could be a mix of the extra stuff you threw in with high sugars for the yeast to eat at and then the two packets of yeast used.

My advice (which is what helped me massively) is to use software to track the brew (it’ll give you target OGs, FGs, ABV and sometimes how much water to use for your mash and your sparge) so you’ll be able to see where you may have gone slightly off-piste!

I would usually wait until the kettle is at 66 degrees before even dropping my grain bill in so. It sure if that may have had an affect?

The idea of giving a mix of sugars, that the yeast can feast on in different stages of fermentation, grabs me by the imagination.

Thanks for the suggestion of using brew software. I will start looking into it.

Does anyone ever boil up sugars in water to use for sparging in the case when it looks like more gravity is needed, or just to add sugar to a brew?

I screwed up with this brew by not sparging fully. Then I remembered that I have a grate bottom I can put into my tank which is perfect for sparging. I won't knowingly be undersparged again.

 

[JustJordds]

Does anyone ever boil up sugars in water to use for sparging in the case when it looks like more gravity is needed, or just to add sugar to a brew?

I haven't no so can't comment, I BIAB and sparge by dunking/ mixing into the water, I think its just to grab that last little bit of sugar from the bag, on some software there is a calculator for if you are under/over your target gravity but we have (somehow) always been pretty bang on.

Good luck with the next brew!

 

[BobShandy]

I haven't no so can't comment, I BIAB and sparge by dunking/ mixing into the water, I think its just to grab that last little bit of sugar from the bag, on some software there is a calculator for if you are under/over your target gravity but we have (somehow) always been pretty bang on.

Good luck with the next brew!

Next time I will make a check list as I have forgotten something in each of my two beer runs. The tank which I ferment in has a steel insert which you can place to sit 1/4 of the way up the 30 liter tank. It has drain holes, so it is perfect for sparging. I can leave the bag of grains on top of that and squeeze it to get most of the sweet liquid out. I can sparge through it. Then pour all of the recovered liquid back into the boil tank for the final boil.

That will be convenient. But the big break through for me was when I bought a wort chiller to use in this present (my second) beer run. It is a world of difference to be able to cool the wort down to pitching temperature in 20-30 minutes.

 

[BobShandy]

I checked the gravity again. I didn't stir before checking the gravity. This is from the top, if that makes any difference.

This reading is 8 days after the last reading. I'm planning on checking each day for the next two days and bottling if it has basically stopped fermenting. I will be washing and re-using this yeast as an experiment.

OG	1.050
Gravity now	1.004
ABV	6.04%
Apparent attenuation	92%

It seems to be slowing down. That attenuation is phenomenal. I checked the gravity very thoroughly. The beer has a good taste. It is very dry, as you can imagine.

 

[BobShandy]

A few days ago I moved the tank around and inadvertently re-started bubbling. That lasted for about a day. I left the tank out for a couple of nights to cold crash it, hoping that the yeast would fall to the bottom.

This evening I bottled. The gravity was now 6.1% to 6.17%. I used an auto-siphon to transfer from my fermenter to a kettle, with a tap, that I was using for bottling. I had boiled sugar in water to prime, and I added this (cool) to the bottling tank. There was about 27 litres in the tank. This is because I put too much sugar water in to my tank to boost gravity at the start.

The hand capper I got from someone turned out to be a nightmare. It was warped.

The fermenter has yeast all over the bottom. The cold crash seems to have worked. I sealed it up and I will try to harvest the yeast tomorrow to do another batch in a while.

 

[Jan.]

I checked the gravity again. I didn't stir before checking the gravity. This is from the top, if that makes any difference.

This reading is 8 days after the last reading. I'm planning on checking each day for the next two days and bottling if it has basically stopped fermenting. I will be washing and re-using this yeast as an experiment.

OG	1.050
Gravity now	1.004
ABV	6.04%
Apparent attenuation	92%

It seems to be slowing down. That attenuation is phenomenal. I checked the gravity very thoroughly. The beer has a good taste. It is very dry, as you can imagine.

You said that the temperature you mashed at was lower than the last time and mention it around 64C. This would have activated a lot of Beta amylase which produces more fermentable sugars. So your initial SG reading of 1.034 would be composed mostly of fermentable sugars.

Then you added brown sugar, caster sugar, honey and maple syrup which are all completely fermentable as well (the maple syrup and the honey may have slight amounts of unfermentable sugars but probably irrelevant amounts). Then the water content of the maple syrup and honey would have watered down the original wort increasing the fermentability further.

So the additional 16 points for gravity (1.034 to 1.050) would have fermented completely. If you hadn't have added the additional sugar then the attenuation would have been lower. 1.034 to 1.004 would have been 88% which is actually still higher than the 82% stated by fermentis as the max attenuation but probably because of the lower mash temperature and more fermemtable wort.

I don't actually know the wort composition used by a manufaturer to measure the max attenuation. Anyone know?

Either way, sorry to geek out a bit but the most important factor is how good the beer tastes so fingers crossed.

Reusing yeast is hugely satisfying and can save you money. I love doing it but it may be best to give the yeast a quick rinse before reusing. Check this site Yeast Washing: How to reuse brewing yeast to save money - BEER CRAFTR

 

[BobShandy]

I am like a dog with two dicks, given all the possibilities of brewing. This yeast which I will be re-using will go into an a similar recipe, but without the sugar (hopefully). Then I'm planning on trying some pressure fermentation [but not with the same yeast, which has adapted to normal pressure.]