Publication - Research and analysis

Distillery by-products, livestock feed and bio-energy use: report

Published: 1 Jul 2019
Directorate:
Agriculture and Rural Delivery Directorate
Part of:
Farming and rural
ISBN:
9781787819566

We commissioned this report in response to concerns by livestock farmers about the impact of anaerobic digestion and bio-energy on the availability of distillery by-product for use as livestock feed in Scotland.

48 page PDF

857.1 kB

48 page PDF

857.1 kB

Contents
Distillery by-products, livestock feed and bio-energy use: report
3. Use of Scotch whisky distillery by-products in livestock feed

48 page PDF

857.1 kB

3. Use of Scotch whisky distillery by-products in livestock feed

Overview of distillery by-products as livestock feed

18. A range of by-products suitable for livestock feed are produced from the malt and grain distilling processes as outlined in the following table. These by-products have differing characteristics which determine their suitability in the feed rations of different species and classes of livestock. In general, cattle are the most suitable target for these feeds with some limited use in sheep and pigs. Any feeds which have originated in a copper malt still (pot ale syrup, Barley DDGS) cannot be used for sheep feed due to the high levels of copper which sheep are particularly sensitive to.

Table 3. Summary of distillery feed by-products and use

Spirit Product Type Livestock

Malt

Draff

Wet

Cattle, sheep

Malt

Pot ale syrup

Liquid

Cattle, pigs

Malt

Malt DDGS

Pellet

Cattle

Grain

Grain moist feeds

Wet

Cattle

Grain

Spent wash syrup

Liquid

Cattle, sheep

Grain

Wheat/Maize DDGS

Pellet

Cattle, sheep

Source: SRUC. Note - * Distiller’s Dark Grains with Solubles (DDGS)

Appendix 1 outlines the inputs, process flows and product outputs involved in malt and grain spirit production.

Appendix 3 details the nutritional value of distillery feedstocks.

19. Unprocessed feeds (draff, moist grain feeds) have a high water content (70-80%) which raises transport costs per unit of dry matter and makes storage more difficult. Draff can be stored by ensiling in clamps alongside silage during the summer months. In practice the quantity of surplus draff which can be preserved in this way is restricted by the availability of clamp space and the limited duration of the grass silage harvest. Effective storage requires experience and losses can be high if not undertaken with care.

20. Pot ale syrup is a liquid by-product, it is a palatable medium to dark brown, viscous syrup that resembles molasses in appearance. The dry matter content is variable depending on the producer. A range of 30-50% dry matter is common. This can make it difficult for handling and storage.

21. Dried and pelletised feeds (barley, wheat and maize dark grains) have a low moisture content (<10%) and can be readily stored and transported economically.

22. Demand for draff from farms in the vicinity of each distillery can at times be insufficient particularly in the summer when grass growth is strongest and the need for feed purchases is reduced. At these times draff might be hauled by road from the North of Scotland to the Central Belt and into the North of England to find demand. This raises the cost of draff to the farmer in these more distant regions. Conversely in winter, local feed demand for draff increases and the draff may be utilised by farms closer to the distillery. It is estimated that around (78%) of distillery by-products used in feed are consumed in Scotland and (22%) (Table 7b) are exported mainly to the north of England.

Estimated quantities of Scotch whisky distillery by-products used in livestock feed

23. Given estimates of the total potential output of distillery by-products (Figure 1, Table 2), further work is then required to determine the quantity that was actually used for animal feed. Given the lack of official statistics in this area SRUC prepared estimates based on discussions with the livestock feed supply trade. These indicate that total usage of Scotch whisky distillery by-products used for animal feed in the UK in 2019 is likely to be around 142,800t of dry matter equivalent or 405,000t on a fresh weight basis. These figures encompass a wide range of feed types and moisture contents as detailed in Table 4.

Table 4. Estimated quantities of Scotch whisky distillery by-products used in UK animal feed in 2019

Fresh weight
(t)
Dry matter
(%)
Dry matter equivalent
(t)

Draff

270,000

22%

59,400

Pot Ale Syrup

35,000

42%

14,700

Malt DDGS

-

90%

-

305,000

74,100

Grain moist feeds

20,000

30%

6,000

Spent wash syrup

15,000

28%

4,200

Grain DDGS

65,000

90%

58,500

100,000

68,700

Total

405,000

142,800

Source: SRUC and trade sources.

24. Trade estimates (feed compounders and brokers) of actual usage in feed are lower than estimates of total distillery by-product output prepared by SRUC (based on spirit production and grain use – Figure 1, Table 2, Appendix 2).

25. For malt whisky, trade estimates indicate that 74,100t DM of by products will be used for animal feed in 2019 compared to SRUC estimated total malt whisky by-product output of 221,370 t DM. This equates to 33% utilisation in feed. For grain whisky (produced from wheat and maize) trade estimates indicate usage in feed of 68,700t DM compared to SRUC estimated total grain whisky by-product output of 221,640t DM. This equates to 31% utilisation in feed. The average across all distillery by-products is 32% utilisation in feeds.

26. The difference between the potential output of distillery by-products and the actual use in feed is due to a range of factors:

  • Collection of draff by farmers straight from distilleries (small scale only)
  • Non-feed uses (such as bio-energy)
  • Spreading to land as a soil improver and disposal to sea

27. A comparison of historic trade estimates of the quantities of Scotch whisky distillery by-products used for animal feed (Table 5) in the UK indicates there is expected to have been a 57% reduction in feed use over the seven year period from 2012 to 2019.

Table 5. UK feed use of Scotch whisky distillery by-products 2012 to 2019

2012
(t DM)
Dry Matter Equivalent
2019
(t DM)
Change
(t DM)
Change
(%)
Malt Distilling

Draff

75,000

59,400

- 15,600

-21%

Pot Ale Syrup

25,200

14,700

- 10,500

-42%

Malt DDGS

67,500

-

- 67,500

-100%

Sub total

167,700

74,100

- 93,600

-56%

GRAIN DISTILLING

Grain moist feeds

45,000

6,000

- 39,000

-87%

Spent wash syrup

22,500

4,200

- 18,300

-81%

Grain DDGS

99,000

58,500

- 40,500

-41%

Sub total

166,500

68,700

- 97,800

-59%

All whisky by-products

334,200

142,800

-191,400

-57%

Source: SRUC and trade sources.

28. The largest falls in by-product use in feed have been in grain distilling by-products. There are a number of explanations for this:

  • Between 2012 and 2019 it is expected that grain whisky output will have fallen 22% while malt whisky output will have risen by 8% - as a result total grain distillery by-product availability has fallen, irrespective of its use[6].
  • In addition there has been a greater uptake of bio-energy production at grain whisky distilleries aided by their larger scale. There are only seven Scotch grain whisky distilleries in Scotland and at an average capacity of 59 million Litres of Pure Alcohol (LPA) they are significantly larger than the average malt distillery of 3 million LPA capacity[7]. This increased scale makes investment in bio-energy production more feasible at grain distilleries as they can access a greater quantity of by-product at the one site.

29. The changes in malt distilling include the cessation of all malt Distiller’s Dark Grains with Solubles (DDGS) production following the closure of the last remaining malt dark grains plant in early 2018.

30. The feed usage figures given in Table 5 are for the whole of the UK as some Scotch whisky distillery by-product is sold elsewhere in the UK. To allow consideration of how these changes have affected feed use in Scotland directly, a further breakdown has been made to show how feed use of whisky distillery by-products has changed in Scotland alone, Table 6. With greater retention of what is available for feed, the impact on Scottish feed availability has been less than the overall UK impact. Further details of the change in use by country are given in the following section.

Table 6. Scottish feed use of Scotch whisky distillery by-products 2012 to 2019* [8]

2012
Use in Scotland
(t DM)
2019
Use in Scotland
(t DM)
Change
(t DM)
Change
(%)
Malt Distilling

Draff

45,000

44,550

-450

-1%

Pot Ale Syrup

10,080

7,350

-2,730

-27%

Malt DDGS

33,750

-

-33,750

Sub total

88,830

51,900

-36,930

-42%

Grain Distilling

Grain moist feeds

27,000

6,000

-21,000

-78%

Spent wash syrup

9,000

4,200

-4,800

-53%

Grain DDGS

49,500

49,725

225

0%

85,500

59,925

-25,575

-30%

0

0

All whisky by-products

174,330

111,825

-62,505

-36%

Source: SRUC and trade sources.

Rising proportion of distillery by-products used for feed in Scotland

31. Since 2012 there have been changes in destination country for Scotch whisky distillery feed by-products. The overall split currently expected for 2019 is that 78% of Scotch distillery by-products will be used in Scotland up from 52% in 2012. Greater retention of Scotch whisky distillery by-product feeds within Scotland and reduced exports to England has meant that local by-product availability for feed within Scotland has not declined as much (-36%) as the fall in overall Scotch whisky distillery by-product output (-57%) would suggest (Tables 7a & 7b). These figures do not include bio-ethanol by-products.

Table 7a. Changes in Scottish use of Scotch whisky distillery by-products 2012 to 2019 (tonnes)

By-product 2012 2019
Sales in Scotland
(t DM)
Sales in England
(t DM)
Sales in Scotland
(t DM)
Sales in England
(t DM)

Malt distilling

88,830

78,870

51,900

22,200

Grain distilling

85,500

81,000

59,925

8,775

All whisky by-products

174,330

159,870

111,825

30,975

Change '12 - '19
(t DM)

- 62,505

-128,895

Change '12 - '19
(%)

-36%

-81%

Source: SRUC and trade sources.

Table 7b. Changes in Scottish use of Scotch whisky distillery
by-products 2012 to 2019 (%)

By-product 2012 2019
Sales in Scotland
(%)
Sales in England
(%)
Sales in Scotland
(%)
Sales in England
(%)

Malt distilling

53%

47%

70%

30%

Grain distilling

51%

49%

87%

13%

All whisky by-products

52%

48%

78%

22%

Source: SRUC and trade sources.

Bio-ethanol feed by-product output in England

32. When consideration of distillery by-products from bio-ethanol plants in the north of England is included, current estimates indicate a 150% increase in supply between 2012 and 2019. This increase helps partly offset the fall in Scotch whisky by-product use in animal feed and when taken together these changes suggest a 13% fall in total UK availability of distillery by-products between 2012 and 2019 (Table 8).

Table 8. Changes in UK wide use of UK distillery by-products 2012 to 2019 (tonnes)

Origin Dry Matter Equivalent
2012
(t DM)
2019
(t DM)
Change
(t DM)
Change
(%)
Scotland

Scotch whisky

Scotch whisky by-products

334,200

142,800

- 191,400

-57%

England

Grain bio-ethanol

England grain bio-ethanol

90,000

225,000

135,000

150%

UK

Total

424,200

367,800

- 56,400

-13%

Source: SRUC and trade sources.

Estimated feed requirement of the Scottish cattle sector

33. In 2017 the livestock sector in Scotland generated output of £1,835m[9] representing 57% of the total output of Scottish agriculture. The Gross Value Added of the individual sectors within Scottish agriculture is not known, as a breakdown is not prepared by Scottish Government. Cattle (beef and dairy) are the most important livestock class within Scottish agriculture and accounted for 40% of total agricultural output and 70% of livestock output in 2017.

34. The beef and dairy sectors in Scotland combined are the livestock sectors most reliant on the types of feed stock typically being used in agricultural and distillery AD plants; e.g. distillery by-products, energy forage crops and other crop by-products. Therefore, it is valid to compare the feed requirement of the Scottish cattle herd with the feedstock requirements of the agricultural and distillery by-product fed AD sector as they are broadly competing for the same feed materials.

35. SRUC has developed a model to estimate the feed requirement of the Scottish livestock sector[10]. The model is based on livestock numbers adapted from the Scottish Government’s June 2018 Agricultural Census and SRUC estimates of feed consumption by animal age and type. These feed estimates are derived from models of energy requirement by livestock class and SRUC estimates of typical feed rations across Scottish farm types. From this model SRUC estimate that in 2018 Scottish beef and dairy cattle are expected to consume around 1.38m t Dry Matter (DM) of concentrate feed, 1.80m t DM of preserved forage and 2.80mt DM of grazed grass (Table 9). These estimates are indicative only.

Table 9. Estimated feed requirement of the Scottish cattle herd 2018

Concentrates

Dairy
(t fresh weight)
Beef
(t fresh weight)
All cattle
% DM

(t DM)

Total

471,000

1,095,000

1,566,000

88%

1,378,000

Forage

Silage

2,055,000

4,218,000

6,274,000

23%

1,443,000

Hay

90,000

90,000

87%

78,000

Straw

323,000

323,000

87%

281,000

Grazing

1,870,000

10,301,000

12,172,000

23%

2,799,000

Total

3,926,000

14,932,000

18,858,000

4,601,00

Total feed

5,980,000

Source: SRUC, note totals may not add due to rounding

36. When comparing total annual cattle feed demand in Scotland of 5.98 million t DM, then the estimated supply of distillery products in Scotland for feed of 142,800t DM in 2019 represents around 2.4% of estimated total feed requirement and 10% of concentrate feed requirement. However, given the high protein content of distillery feeds, the importance to the livestock sector of this feed source is greater since it represents a valuable protein supplement to lower protein forages and grains.


Contact

Email: Gordon.Jackson@gov.scot