Erlenmeyer Flask - 5000 mL

Erlenmeyer Flask - 5000 mL

In Stock
Delivers to ( change ) by as part of our Fast & Free Shipping.
Faster Shipping Available. Details.
60 day no hassle return policy. Details

This Erlenmyer flask is huge, coming in at 5000 ml (5L!), making it the ideal vessel to make a large yeast starter for a 10+ gallon batch. The best brewers make large yeast starters to get their beer fermenting fast, and most of them do so in an Erlenmeyer flask. Large populations of active yeast help ensure flavorful beer free of off flavors. Because this flask is made from borosilicate glass you can move it from a boil into a cold water bath for cooling. This means you can do the whole process in one container, keeping it simple and helping to reduce the risk of contamination when transferring from one container to another.

Double Boiler Method
It is important for your safety to heat water in the flask with a heat source that distributes heat evenly. Morebeer! recommends using the "double boiler method." This process involves using a boiling water bath on the outside of the flask to heat up the water inside the flask. All you need is a kettle 3 gallons or larger. This process is much safer and efficient. If the flask should break or boil over, your kettle will be there to collect the contents, thus keeping your stove clean and keeping you safe.

Safety First: Please take us up on a great deal - save $14.95 when you purchase a 5000ml flask and our BE300 5 gallon stainless steel kettle at the same time. Use Promo code SAFETY1 at checkout.


  • Massive 5L (5000ML) Capacity
  • Made from Borosilicate Glass (also known as Pyrex)
  • Fantastic price for a flask of this size
  • Produced for MoreBeer!

Why make a yeast starter? (from our FAQ)
We build starters for 3 main reasons. First, to ensure yeast health. By making a starter 1-3 days in advance, you ensure that your yeast is healthy and strong and ready to do its job. Second, to create more yeast. By making the starter you will increase the cell count of the yeast, giving you a better chance of keeping bacteria's and wild yeasts from fermenting your wort. Third, if you are making high gravity beers. If you are making a high gravity beer (1.060+) you will need more yeast to start the ferment faster. High gravity beers will also finish more completely when you pitch ample quantities of yeast.

In the lab world, these flasks are known as "Student Grade". Student grade flasks may have small scratches and air bubbles. A great flask for making yeast starters!

Kegland Part Number: KL04008

Item # Y450
Shipping Eligible for Free Shipping Program
Availability California - In Stock
Pennsylvania - In Stock
Weight 7 LBS
Community Q&A

Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 5 questions Browse 5 questions and 69 answers
Why did you choose this?
MoreFlavor Store
Brad K on Nov 25, 2021
I need to make big starters!
Mark M on Nov 13, 2021
Brad K on Nov 25, 2021
Yeast starters
Elias C on Nov 22, 2021
I need to make big starters!
Mark M on Nov 13, 2021
Recommended by a friend
Doug R on Nov 13, 2021
I'll be using this product for yeast starters
Eric E on Nov 6, 2021
great price on giant flask
Jeffery B on Oct 21, 2021
Because you offered the best price and free shipping.
Nicholas A on Oct 16, 2021
Best price on the net.
Larry T on Oct 11, 2021
Halloween costume prop
Ryan G on Oct 11, 2021
great price
paul arthur s on Oct 8, 2021
Lager Starter
Joseph T on Sep 30, 2021
Planning to make yeast starter for 10 gallons or more at a time.
John Nolte on Sep 11, 2021
need an extra
Gianmarco L on Sep 11, 2021
High gravity starters
Erich F on Jul 20, 2021
Big enough for Lager yeast starters
Michael R S on Jun 25, 2021
Starters for 10 gal batches
Dallas E on Jun 25, 2021
make larger starters
colm g on Mar 30, 2021
More beer customer service
Kelly L on Mar 26, 2021
Beer deal
Matthew J on Mar 18, 2021
Deal of the day
kody g on Mar 15, 2021
To overbuild starters
Antonio Martinez on Mar 4, 2021
Wanted a larger flask
Stephen A on Feb 25, 2021
Need for large lager yeast starters
Karl G on Feb 15, 2021
Great price on the big one!
Brennan L on Feb 6, 2021
Big starters, baby!
matt s on Jan 14, 2021
To make starter for lager. 2000ml is too small!
Alexander Osborne on Jan 12, 2021
High capacity so I can make starters for any size beer I plan to brew.
Dylan H on Jan 11, 2021
Perfect for high ABV yeast starter
Robert W on Dec 30, 2020
It’s a gift for my son-in-law
Lynna S on Dec 11, 2020
Last starter ended up all over the place
Valued C on Dec 2, 2020
Sean S on Nov 30, 2020
I need a bigger flask.
kevin s on Nov 28, 2020
Rick Carruth on Nov 28, 2020
For starting yeast
Harold N on Nov 19, 2020
need back up
Michael W on Nov 6, 2020
For lager starter
Jason R on Oct 29, 2020
Excellent price
Michael on Sep 30, 2020
Good reviews and best price
Brant B on Sep 23, 2020
Yeast starter for 10+ gallon batches
Curtis B on Sep 22, 2020
Gianmarco L on Sep 3, 2020
Need something bigger than my 2L for 10 gal batches
Michael A on Aug 27, 2020
it was a gift request
Lisa T on Aug 18, 2020
For making starters for my 15 gallon batches
Valued C on Aug 4, 2020
Need a bigger flask for high gravity starters
SCOTT S. on Jul 16, 2020
right size, right price
Ken M on Jul 8, 2020
LAGER starter
Pete T on Jul 3, 2020
to save on yeast cost
Michael Dean on Jul 3, 2020
I like big flasks...
Philip B on Jun 16, 2020
yeast starters
Dan W on Jun 12, 2020
For brewing beer
Heather B on Jun 10, 2020
Yeast starters
Elias C on Nov 22, 2021
Recommended by a friend
Doug R on Nov 13, 2021
What is the diameter of the bottom of this 5000 mL erlenmeyer flask?
Dennis Ellis on Jan 30, 2018
BEST ANSWER: There may be a touch of variation unit to unit - my numbers differ slightly from Dennis'. On mine the flat part of base is 5+7/8" around the raised flat lip. Widest part is 9". Height is 15".

The volumetric markings on mine are not as close as I would like (probably off by ~ 1/4L or so @3L), so I use a digital scale to measure the added liquid (1kg ~= 1L water at roomish temp).

I don't trust direct heating any flask, especially this big over direct flame, so I never do that - I'd love to hear from others who have success doing this. But I have never had any issues transferring hot liquids into this flask - no cracks, etc. But I have been careful. 5L is a lot of potential pain - better safe than sorry. Cheers!
What size (replacement) foam stopper does this need? 11 1/2? Where do I get this?
Thomas Garten on Feb 18, 2019
BEST ANSWER: Hi Thomas - The #12 foam stopper should work perfectly with the item. Unfortunately, we do not have a specific recommendation for the purchase but a quick google search should bring satisfactory results.
Is the bottom supposed to be flat or concave? I just bought one of these, and the bottom is concave (bows upward in the middle). As a result of this the stir bar falls to the side and stays there, and the stir plate can't spin it. I just spent 30 minutes trying to wiggle it to the middle to get it started, to no avail. What am I doing wrong? Seems to me that if the bottom was flat, this wouldn't be an issue.
James Galvin on Dec 11, 2020
BEST ANSWER: The bottom of Erlenmeyer flasks never seem to be completely flat as you would like. Using a stir bar inside one generally requires a stir plate with a fairly powerful magnet. Especially with large flasks such as a 5000 mL, I can't run the stir feature at anywhere near full speed. When the magnet jumps to the edge of the flask, I simply turn off the stir plate, tilt the flask so only a bottom edge is against the center of the stir plate (where its magnet is). While keeping contact, I slowly rotate the flask until I hear the magnet in the stir plate find the bar in the flask. While maintaining contact with the plate, I then slowly upright the flask and re-center it on the plate. I know the speed limit of my plate, so I can generally prevent this, but it's not a big deal when it happens if you know this trick. Hope it helps.
Using Double Boil Method:... "This process is much safer and efficient. If the flask should break ..." Why would the flask break from boiling if its pyrex?
Austin Woitte on Aug 13, 2019
BEST ANSWER: Well, in a perfect world with perfect quality, you could ignore this advice, if you could be sure you never damage the flask in an undetectable way.... these flask are not to lab quality standards, they are essentially seconds...more prone to failure I suspect.... that said I boil direct, using the same flask at least 30 times so far

4.6 / 5.0
86 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Rated 5 out of 5
Very Happy
I'm extremely happy with this 5000 ml flask. It it is of a high quality and I have no fear of it breaking without the exception of my own clumsiness. It is huge, beautiful and I got it at a very fair price.
November 26, 2021
3 weeks ago
Rated 5 out of 5
Monster flask!
This is for those BIG yeast starters and it works great!
July 12, 2021
5 months ago
Rated 5 out of 5
Buy this one
I bought a 2000ml flask first, but wish I'd gone straight to the 5000. This one is big enough to make any starter you'll ever need and then some. In fact I've started doubling my starters so I can harvest half to keep yeast on hand for strains I use frequently. I boil directly in the flask on my glass top stove and transfer directly to an ice bath in the sink, no issues. If you do boil in the flask you'll need a few drops of fermcap-S to prevent boil overs
May 26, 2021
8 months ago
Rated 5 out of 5
Excellent product for excellent price...
February 19, 2021
9 months ago
Rated 5 out of 5
It works great I boiled in it I chilled in it there was no problem
The flask is genuine. I boiled and chilled in it no problems. The foam stopper fits perfectly!
The flask is genuine. I boiled and chilled in it no problems. The foam stopper fits perfectly!
January 8, 2021
11 months ago
Rated 5 out of 5
Excellent! And thank you to the customer service team for awesome service!!
September 30, 2020
1 year ago
Rated 4 out of 5
Bigger is better!
The size of this thing is mammoth. It is just what you need to for yeast starters for high alcohol brews. It would have gotten 5 stars but there are bubbles in the glass in certain areas, which means I have to boil the malt in a pot before transferring the hot liquid to the flask. I don't want it to shatter. Small inconvenience in my mind.
September 17, 2020
1 year ago
Rated 4 out of 5
Big Beer Needs Big Starter
This is the Mac Daddy Flask. Big beer plans need a big starter. A gallon on the stir plate makes it happen. Discounted 1 star for the graduation marks at 4 & 5 liters being off by quite a bit.
September 8, 2020
over 3 years ago
Rated 3 out of 5
Good flask with bad volume markings
For the price, this is an excellent 5-liter flask, just the thing for huge yeast starters. Be warned, though, that the volume graduations are not accurate, at least not on my model. The 2,000 mL mark is spot on, but others are not. I wouldn't discourage potential buyers from getting one of these if you just need a big, affordable vessel to contain a starter, but know that you can't trust the graduations on the side. Use a scale and you'll be fine, though.
June 26, 2020
1 year ago
Rated 5 out of 5
Great Product
I mean, it works great. When you want the flexibility to make starters of any size, just get a 5L.
April 29, 2020
1 year ago